Determination of biologically active substances. Chemistry of biologically active substances. Enzymes and nucleic acids

In order for an athlete’s body to maintain performance and normal functioning after intense training and competitions, it needs a balanced diet depending on the individual needs of the body, which must correspond to the athlete’s age, gender and sport. To restore the normal functioning of the body systems, the athlete must receive a sufficient amount of proteins, fats and carbohydrates along with food, as well as biologically active substances– vitamins and mineral salts.

As you know, the physiological needs of the body depend on the constantly changing living conditions of the athlete, which does not allow a qualitatively balanced diet.

However, the human body has regulatory properties and can absorb the necessary nutrients from food in the quantities it needs at the moment. However, these methods of adaptation of the body have certain limits.

The fact is that the body cannot synthesize some valuable vitamins and essential amino acids during the metabolic process, and they can only come from food. If the body does not receive them, the diet will be unbalanced, as a result of which performance decreases and there is a threat of various diseases.

Squirrels

These substances are a must for weight lifters because they help build muscle mass. Proteins are formed in the body by absorbing them from food. In terms of nutritional value, they cannot be replaced with carbohydrates and fats. Sources of proteins are products of animal and plant origin.

Proteins, which are divided into replaceable (about 80%) and essential (20%). Nonessential amino acids are synthesized in the body, but the body cannot synthesize essential ones, so they must be supplied with food or with the help of sports nutrition.

Protein is the main plastic material. Skeletal muscle contains approximately 20% protein. Protein is part of enzymes that accelerate various reactions and ensure the intensity of metabolism. Protein is also contained in hormones that are involved in the regulation of physiological processes. Protein is involved in muscle contraction.

In addition, protein is an integral part of hemoglobin and ensures the transport of oxygen. Blood protein (fibrinogen) is involved in the process of blood clotting. Complex proteins (nucleoproteins) contribute to the inheritance of the body's qualities. Protein is also a source of energy needed for exercise: 1 g of protein contains 4.1 kcal.

Muscle tissue consists of protein, so bodybuilders, to maximize muscle size, introduce a lot of protein into their diet, 2-3 times more than the recommended amount. It should be noted that the belief that consuming large amounts of protein increases strength and endurance is erroneous. The only way to increase muscle size without harm to health is regular training.

If the athlete uses a large number of protein foods, this leads to weight gain. Since regular training increases the body's need for protein, most athletes consume protein-rich foods, taking into account the norm calculated by nutritionists.

Protein-fortified foods include meat, meat products, fish, milk and eggs.

Meat is a source of complete proteins, fats, vitamins (B1, B2, B6) and minerals (potassium, sodium, phosphorus, iron, magnesium, zinc, iodine). Meat products also contain nitrogenous substances that stimulate the secretion of gastric juice, and nitrogen-free extractive substances that are extracted during cooking.

Kidneys, liver, brains, lungs also contain protein and have high biological value. In addition to protein, liver contains a lot of vitamin A and fat-soluble compounds of iron, copper and phosphorus. It is especially useful for athletes who have undergone severe injury or surgery.

A valuable source of protein is sea and river fish. In terms of the presence of nutrients, it is not inferior to meat. Compared to meat, the chemical composition of fish is somewhat more diverse. It contains up to 20% proteins, 20-30% fats, 1.2% mineral salts (potassium salts, phosphorus and iron). Sea fish contains a lot of fluorine and iodine.

In the nutrition of athletes, preference is given to chicken and quail eggs. The use of waterfowl eggs is undesirable, as they can be contaminated with pathogens of intestinal infections.

In addition to proteins of animal origin, there are proteins of plant origin, found mainly in nuts and legumes, as well as in soy.

Legumes

Legumes are a nutritious and satisfying source of low-fat protein, contain insoluble fiber, complex carbohydrates, iron, vitamins C and B. Legumes are the best substitute for animal protein, lower cholesterol, and stabilize blood sugar.

Including them in the diet of athletes is necessary not only because legumes contain a large amount of protein. This food allows you to control your body weight. It is better not to consume legumes during competitions, as they are quite difficult to digest food.

Soybeans contains high-quality protein, soluble fiber, protease inhibitors. Soy products are good substitutes for meat and milk and are indispensable in the diet of weightlifters and bodybuilders.

Nuts, in addition to vegetable protein, contain B vitamins, vitamin E, potassium, and selenium. Various types of nuts are included in the diet of athletes as a nutritious product, a small amount of which can replace a large amount of food. Nuts enrich the body with vitamins, proteins and fats, reducing the risk oncological diseases, prevent many heart diseases.

Fats (lipids)

Fats play an important role in regulating metabolism and contributing to the normal functioning of the body. A lack of fat in the diet leads to skin diseases, vitamin deficiencies and other diseases. Excess fat in the body leads to obesity and some other diseases, which is not acceptable for people involved in sports.

When fats enter the intestines, the process of their breakdown into glycerol and fatty acids begins. These substances then penetrate the intestinal wall and are converted back into fats, which are absorbed into the blood. It transports fats to tissues, where they are used as energy and building materials.

Lipids are part of cellular structures, so they are necessary for the formation of new cells. Excess fat is stored as adipose tissue reserves. It should be noted that the normal amount of fat in an athlete is on average 10-12% of body weight. During the oxidation process, 9.3 kcal of energy is released from 1 g of fat.

The healthiest ones are milk fats, which are found in butter and ghee, milk, cream and sour cream. They contain a lot of vitamin A and other substances beneficial to the body: choline, tocopherol, phosphatides.

Vegetable fats (sunflower, corn, cottonseed and olive oils) are a source of vitamins and contribute to the normal development and growth of a young body.

Vegetable oil contains polyunsaturated fatty acids and vitamin E. Vegetable oil intended for heat treatment must be refined. If vegetable oil is used fresh as a dressing for foods and dishes, it is better to use unrefined oil rich in vitamins and nutrients.

Fats are rich in phosphorus-containing substances and vitamins and are a valuable energy source.
Polyunsaturated fatty acids help improve immunity and strengthen the walls blood vessels and activation of metabolism.

One of the recent television programs reported that Russians occupy one of the last places in terms of awareness of the composition of food products. It turns out that only 5% Russian buyers are interested in the chemical composition of products, which is indicated on the label. Moreover, they are interested in the number of calories, proteins, fats and carbohydrates, but have not heard of any (omega) fatty acids

Carbohydrates

In dietetics, carbohydrates are divided into simple (sugar) and complex, more important from the point of view rational nutrition. Simple carbohydrates are called monosaccharides (fructose and glucose). Monosaccharides quickly dissolve in water, which facilitates their passage from the intestines into the blood.

Complex carbohydrates are made up of several monosaccharide molecules and are called polysaccharides. Polysaccharides include all types of sugars: milk, beet, malt and others, as well as fiber, starch and glycogen.

Glycogen is the most important element for the development of endurance in athletes, it belongs to polysaccharides and is produced in the body by animals. Stored in the liver and muscle tissue, meat contains almost no glycogen, since after the death of living organisms it breaks down.

The body absorbs carbohydrates in a fairly short time. Glucose, entering the blood, immediately becomes a source of energy perceived by all tissues of the body. Glucose is necessary for the normal functioning of the brain and nervous system.

Some carbohydrates are contained in the body in the form of glycogen, which in large quantities can be converted into fat. To avoid this, you should calculate the calorie content of food consumed and maintain a balance of calories consumed and calories received.

Rye and wheat bread, crackers, cereals (wheat, buckwheat, pearl barley, semolina, oatmeal, barley, corn, rice), bran and honey are rich in carbohydrates.

Corn grits– a valuable source of complex carbohydrates, fiber and thiamine. This is a high-calorie, but not fatty product. Athletes should use it for the purpose of prevention coronary disease heart disease, certain types of cancer, and obesity.

The high quality carbohydrates found in grains are best replacement carbohydrates found in pasta and bakery products. It is recommended to introduce unmilled grains of some types of cereals into the diet of athletes.

• Barley is widely used for preparing sauces, seasonings, and first courses;
• Millet is served as a side dish for meat and fish dishes. The grains of the plant are rich in phosphorus and B vitamins;
• Wild rice contains high-quality carbohydrates, significant amounts of protein and B vitamins;
• Quinoa is a South American grain used to make puddings, soups and main courses. Contains not only carbohydrates, but also large amounts of calcium, protein and iron;
• Wheat is often used in sports nutrition as a substitute for rice.

Unmilled or coarsely ground grains are healthier than ground grains or processed grains into flakes. Grain that has not undergone special technological processing is rich in fiber, vitamins and microelements. Dark grains (such as brown rice) do not cause osteoporosis, unlike processed grains such as semolina or white rice.

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Minerals

These substances are part of tissues and participate in their normal functioning, maintaining the necessary osmotic pressure in biological fluids and the constancy of the acid-base balance in the body. Let's look at the main minerals.

Potassium is part of the cells, and sodium is contained in the intercellular fluid. For normal functioning of the body, a strictly defined ratio of sodium and potassium is necessary. It ensures normal excitability of muscle and nerve tissue. Sodium is involved in maintaining constant osmotic pressure, and potassium affects the contractile function of the heart.

Both excess and deficiency of potassium in the body can lead to disturbances in the functioning of the heart. vascular system.

Potassium is present in varying concentrations in all body fluids and helps maintain water-salt balance. Rich natural sources of potassium include bananas, apricots, avocados, potatoes, dairy products, and citrus fruits.

Calcium is part of the bones. Its ions are involved in the normal activity of skeletal muscles and the brain. The presence of calcium in the body promotes blood clotting. Excessive amounts of calcium increase the frequency of contractions of the heart muscle, and in very high concentrations can cause cardiac arrest. The best source of calcium is dairy products; broccoli and salmon fish are also rich in calcium.

Phosphorus part of cells and intercellular tissues. It is involved in the metabolism of fats, proteins, carbohydrates and vitamins. Phosphorus salts play an important role in maintaining the acid-base balance of the blood, strengthening muscles, bones and teeth. Legumes, almonds, poultry and especially fish are rich in phosphorus.

Chlorine is part of the hydrochloric acid of gastric juice and is found in the body in combination with sodium. Chlorine is essential for the functioning of all cells in the body.

Iron is a component of some enzymes and hemoglobin. It participates in the distribution of oxygen and promotes oxidative processes. A sufficient amount of iron in the body prevents the development of anemia, decreased immunity, and deterioration of brain function. Natural sources of iron are green apples, fatty fish, apricots, peas, lentils, figs, seafood, meat, and poultry.

Bromine found in blood and other fluids of the body. It enhances inhibition processes in the cerebral cortex and thereby promotes a normal relationship between inhibitory and excitatory processes.

Iodine is part of the hormones produced thyroid gland. Lack of iodine can cause disruption of many body functions. Sources of iodine include iodized salt, sea fish, algae and other seafood.

Sulfur is part of proteins. It is contained in hormones, enzymes, vitamins and other compounds that participate in metabolic processes. Sulfuric acid neutralizes harmful substances in the liver. A sufficient presence of sulfur in the body lowers cholesterol levels and prevents the development of tumor cells. Onion crops, green tea, pomegranates, apples, and various types of berries are rich in sulfur.

Zinc, magnesium, aluminum, cobalt and manganese are important for the normal functioning of the body. They are present in cells in small quantities, which is why they are called microelements.

Magnesium– a metal involved in biochemical reactions. It is necessary for muscle contraction and enzyme function. This microelement strengthens bone tissue and regulates heart rate. Sources of magnesium include avocados, brown rice, wheat germ, sunflower seeds, and amaranth.

Manganese– a microelement necessary for the formation of bone and connective tissues, the work of enzymes involved in carbohydrate metabolism. Pineapples, blackberries, and raspberries are rich in manganese.

Vitamins

Vitamins are biologically active organic substances that play an important role in metabolism. Some vitamins are contained in enzymes that ensure the occurrence of biological reactions, others are in close connection with the endocrine glands.

Vitamins support the immune system and ensure high performance of the body. A lack of vitamins causes disturbances in the normal functioning of the body, which are called vitamin deficiencies. The body's need for vitamins increases significantly with increasing atmospheric pressure and temperature environment, as well as during physical activity and certain diseases.

Currently, about 30 varieties of vitamins are known. Vitamins are divided into two categories: fat-soluble And water-soluble. Fat-soluble vitamins are vitamins A, D, E, K. They are found in body fat and do not always require regular intake from the outside; if there is a deficiency, the body takes them from its resources. Excessive amounts of these vitamins can be toxic to the body.

Water-soluble vitamins are B vitamins, folic acid, biotin, pantothenic acid. Due to their low solubility in fats, these vitamins hardly penetrate into adipose tissue and do not accumulate in the body, except for vitamin B12, which accumulates in the liver. Excess water-soluble vitamins are excreted in the urine, so they have low toxicity and can be taken in fairly large quantities. Overdose sometimes leads to allergic reactions.

For athletes, vitamins are especially important substances for a variety of reasons.

• Firstly, vitamins are directly involved in the processes of development, work and growth of muscle tissue, protein synthesis and ensuring cell integrity.
• Secondly, during active physical activity, many beneficial substances are consumed in large quantities, so there is an increased need for vitamins during training and competitions.
• Thirdly, special vitamin supplements and natural vitamins enhance growth and increase muscle performance.

The most important vitamins for sports

Vitamin E(tocopherol). Promotes normal reproductive activity of the body. A lack of vitamin E can lead to irreversible changes in muscles, which is unacceptable for athletes. This vitamin is an antioxidant that protects damaged cell membranes and reduces the amount of free radicals in the body, the accumulation of which leads to changes in cell composition.

Rich in vitamin E vegetable oils, germs of cereal plants (rye, wheat), green vegetables. It should be noted that vitamin E increases the absorption and stability of vitamin A. The toxicity of vitamin E is quite low, but in case of overdose it can cause side effects – skin diseases, unfavorable changes in the sexual sphere. Vitamin E should be taken with a small amount of fat-containing food.

Vitamin H(biotin). Participates in the reproductive processes of the body and affects fat metabolism and the normal functioning of the skin. Biotin plays a vital role in the synthesis of amino acids. You should know that biotin is neutralized by avidin, found in raw egg whites. When consuming too much raw or undercooked eggs, athletes may experience problems with bone and muscle growth. The source of biotin is yeast, egg yolk, liver, grains and legumes.

Vitamin C(ascorbic acid). Contained in enzymes and catalysts. Participates in redox reactions, metabolic processes of carbohydrates and proteins. If there is a lack of vitamin C in food, a person can get scurvy. It should be noted that in most cases this disease leads athletes to professional incompetence. His characteristic symptoms– rapid fatigue, bleeding and loosening of gums, tooth loss, hemorrhages in muscles, joints and skin.

Vitamin C improves immunity. It is an excellent antioxidant that protects cells from free radicals and accelerates the process of cell regeneration. In addition, ascorbic acid takes part in the formation of collagen, which is the main material of connective tissues, so sufficient levels of this vitamin in the body reduce injuries during increased power loads.

Vitamin C promotes better absorption of iron, necessary for the synthesis of hemoglobin, and is also involved in the process of testosterone synthesis. Vitamin C has the highest solubility in water, so it is quickly distributed throughout the fluids in the body, as a result of which its concentration decreases. The greater the body weight, the lower the vitamin content in the body at the same consumption rate.

In athletes building or participating in strength sports, the need for ascorbic acid is increased and increases with intense training. The body is not able to synthesize this vitamin and receives it from plant foods.

Daily consumption of ascorbic acid is necessary to maintain the natural balance of substances in the body, while in stressful situations the norm of vitamin C increases by 2 times, and during pregnancy - by 3 times.

Blackcurrant and rosehip berries, citrus fruits, bell peppers, broccoli, melons, tomatoes and many other vegetables and fruits are rich in ascorbic acid.

An overdose of vitamin C can lead to allergic reactions, itching and irritation of the skin; large doses can stimulate the development of tumors.

Vitamin A. Ensures the normal condition of the epithelial integument of the body and is necessary for cell growth and reproduction. This vitamin is synthesized from carotene. With a lack of vitamin A in the body, the immune system sharply decreases, the mucous membranes and skin become dry. Vitamin A is of great importance for vision and normal sexual function.

In the absence of this vitamin, sexual development is delayed in girls, and sperm production stops in men. For athletes, it is of particular importance that vitamin A is actively involved in protein synthesis, which is fundamental for muscle growth. In addition, this vitamin is involved in the body’s accumulation of glycogen, the main energy store.

For athletes, a fairly small amount of vitamin A is usually included. However, high physical activity does not contribute to the accumulation of vitamin A. Therefore, before important competitions, you should consume more foods containing this vitamin.

Its main source is vegetables and some fruits, colored red and orange colors: carrots, apricots, pumpkin, as well as sweet potatoes, dairy products, liver, fish fat, egg yolks.

Great care should be taken when increasing doses of vitamin A, since exceeding them is dangerous and leads to serious illnesses - jaundice, general weakness, peeling of the skin. This vitamin is fat soluble and is therefore absorbed by the body only when consumed with fatty foods. When eating raw carrots, it is recommended to season them with vegetable oil.

B vitamins. These include vitamins B1 (thiamine), B2 (riboflavin), B6, B12, V3 (nicotinic acid), pantothenic acid and others.

Vitamin B1(thiamine) is involved in the metabolism of proteins, fats and carbohydrates. Nervous tissue most sensitive to thiamine deficiency. When there is a lack of it, it is sharply disrupted metabolic processes. Without thiamine in food, severe beriberi disease can develop. It manifests itself in metabolic disorders and disruption of normal
functioning of the body.

A lack of vitamin B1 causes weakness, indigestion, and disorders of the nervous system and cardiac activity. Thiamine is involved in the process of protein synthesis and cell growth. Effective in building muscle.

Vitamin B1 is involved in the formation of hemoglobin, which is important for enriching muscles with oxygen during active training. In addition, this vitamin generally improves productivity and regulates energy expenditure. The more intense the workout, the more thiamine is required.

Thiamine is not synthesized in the body, but comes from plant foods. Yeast and bran, meat by-products, legumes and grains are especially rich in it.

Vitamin B2(riboflavin). Contained in all cells of the body and is a catalyst for redox reactions. With a lack of riboflavin, a decrease in temperature, weakness, and dysfunction are observed. gastrointestinal tract and damage to mucous membranes. Riboflavin is involved in the most important processes of energy release: glucose metabolism, fatty acid oxidation, hydrogen uptake, protein metabolism.

There is a direct relationship between fat-free body weight and the amount of riboflavin in food. For women, the need for vitamin B2 is higher than for men. This vitamin increases the excitability of muscle tissue. Natural sources of riboflavin include liver, yeast, grains, meat and dairy products.

Pantothenic acid deficiency can cause liver dysfunction, and insufficient amounts folic acid- anemia.

Vitamin B3(a nicotinic acid). Plays an important role in the synthesis of fats and proteins and affects the growth of the body, the condition of the skin and the functioning of the nervous system. Contained in enzymes that catalyze redox processes in tissues. Providing the body with enough of this vitamin improves muscle nutrition during training.

Nicotinic acid causes vascular constriction, which helps bodybuilders look more muscular in competitions, but it must be borne in mind that large doses of this acid reduce performance and slow down fat burning.

Vitamin B3 enters the body with food. It is especially required by the body for diseases of the liver, heart, mild forms of diabetes and peptic ulcer. A lack of vitamin can lead to pellagra, which is characterized by damage to the skin and disorders of the gastrointestinal tract.

A large number of nicotinic acid contain yeast and bran, tuna meat, liver, milk, eggs, mushrooms.

Vitamin B4(choline). It is part of lecithin, which is involved in the construction of cell membranes and the formation of blood plasma. Has a lipotropic effect. Sources of vitamin B4 are meat, fish, soy, and egg yolks.

Vitamin B6(pyridoxine). Contained in enzymes involved in the breakdown of amino acids. This vitamin is involved in protein metabolism and affects the level of hemoglobin in the blood. Pyridoxine is necessary for athletes in higher doses, as it promotes the growth of muscle tissue and increased performance. Sources of vitamin B6 are young poultry meat, fish, meat by-products, pork, eggs, and whole rice.

Vitamin B9(folic acid). Stimulates and regulates the process of hematopoiesis, prevents anemia. Participates in the synthesis of the genetic composition of cells, the synthesis of amino acids, and hematopoiesis. The vitamin should be present in the diet during pregnancy and intense physical activity. Natural sources of folic acid are leafy vegetables (lettuce, spinach, Chinese cabbage), fruits, legumes.

Vitamin B12. Increases appetite and eliminates gastrointestinal disorders. With its deficiency, the level of hemoglobin in the blood decreases. Vitamin B12 is involved in metabolism, hematopoiesis and normal functioning of the nervous system. It is not synthesized and enters the body with food.

The liver and kidneys are rich in vitamin B12. Contained only in food of animal origin, therefore athletes following a low-fat or vegetarian diet should consult a doctor about including this vitamin in the diet in the form of various preparations. Lack of vitamin B12 leads to pernicious anemia, accompanied by impaired hematopoiesis.

Vitamin B13(orotic acid). It has increased anabolic properties and stimulates protein metabolism. Takes part in the synthesis of nucleic acids. Included in multivitamin preparations, the natural source is yeast.

Vitamin D very important for the body's absorption of calcium and phosphorus. This vitamin contains a large amount of fat, so many athletes avoid its use, which leads to violations bone tissue. Vitamin D is rich in dairy products, butter, eggs; it is formed in skin when exposed to sunlight. This substance stimulates the growth of the body and participates in carbohydrate metabolism.

Vitamin D deficiency leads to dysfunction musculoskeletal system, bone deformations and respiratory function. Regular inclusion in the diet of foods and preparations containing this vitamin helps rapid recovery body after multi-day competitions and increased physical activity, better healing of injuries, increased endurance, and good health athletes. An overdose of vitamin D causes a toxic reaction and also increases the likelihood of developing tumors.

Fruits and vegetables do not contain this vitamin, but they do contain provitamin D sterols, which are converted to vitamin D when exposed to sunlight.

Vitamin K. Regulates blood clotting. It is recommended to take it under heavy loads and the danger of microtrauma. Reduces blood loss during menstruation, hemorrhages, and injuries. Vitamin K is synthesized in tissues and, if present in excess, can cause blood clots. The source of this vitamin is green crops.

Vitamin B15. Stimulates oxidative processes in cells.

Vitamin P. With its deficiency, the strength of capillaries is impaired and their permeability increases. This leads to increased bleeding.

Pantothenic acid. Promotes normal course in the body of many chemical reactions. With its deficiency, weight decreases, anemia develops, the functions of some glands are disrupted, and growth is stunted.

Since the needs of athletes for vitamins are very different, and consuming them in their natural form is not always possible, a good solution is to use drugs that contain a large amount of vitamins, micro- and macroelements in dosage form.

Destruction of biologically active substances

All biologically active substances can be destroyed. Destruction is promoted not only by natural processes, but also by improper use, storage and use of products containing biologically active substances.

Doctor of Biological Sciences, Professor V. M. Shkumatov;

Deputy General Director for Issues

innovative development of RUE "Belmedpreparaty"

Candidate of Technical Sciences T. V. Trukhacheva

Leontyev, V. N.

Chemistry of biologically active substances: an electronic course of lecture texts for students of the specialty 1-48 02 01 “Biotechnology” of full-time and part-time forms of study / V. N. Leontiev, O. S. Ignatovets. – Minsk: BSTU, 2013. – 129 p.

The electronic course of lecture texts is devoted to the structural and functional features and chemical properties of the main classes of biologically active substances (proteins, carbohydrates, lipids, vitamins, antibiotics, etc.). Methods of chemical synthesis and structural analysis of the listed classes of compounds, their properties and effects on biological systems, as well as distribution in nature.

Topic 1. Introduction
The chemistry of biologically active substances studies the structure and biological functions of the most important components of living matter, primarily biopolymers and low-molecular bioregulators, paying special attention to elucidating the patterns of the relationship between structure and biological action. Essentially, it is the chemical foundation of modern biology. By developing the fundamental problems of the chemistry of the living world, bioorganic chemistry contributes to solving the problems of obtaining practically important drugs for medicine, Agriculture, a number of industries.

Objects of study: proteins and peptides, nucleic acids, carbohydrates, lipids, mixed biopolymers - glycoproteins, nucleoproteins, lipoproteins, glycolipids, etc.; alkaloids, terpenoids, vitamins, antibiotics, hormones, prostaglandins, growth substances, pheromones, toxins, as well as synthetic medications, pesticides, etc.

Research methods: the main arsenal consists of methods organic chemistry, however, to solve structural and functional problems, a variety of physical, physicochemical, mathematical and biological methods are also used.

Main goals: isolation of the studied compounds in an individual state using crystallization, distillation, various types chromatography, electrophoresis, ultrafiltration, ultracentrifugation, countercurrent distribution, etc.; establishment of structure, including spatial structure, based on approaches of organic and physical-organic chemistry using mass spectrometry, various types of optical spectroscopy (IR, UV, laser, etc.), X-ray diffraction analysis, nuclear magnetic resonance, electron paramagnetic resonance, optical dispersion rotation and circular dichroism, fast kinetics methods, etc. in combination with computer calculations; chemical synthesis and chemical modification of the studied compounds, including complete synthesis, synthesis of analogues and derivatives, in order to confirm the structure, clarify the relationship between structure and biological function, and obtain practically valuable drugs; biological testing of the resulting compounds in vitro And in vivo.

The most common functional groups found in biomolecules are:

hydroxyl (alcohols)	amino group (amines)
aldehydic (aldehydes)	amide (amides)
carbonyl (ketones)	ester
carboxylic (acid)	ethereal
sulfhydryl (thiols)	methyl
disulfide	ethyl
phosphate	phenyl
guanidine	imidazole

Topic 2. Proteins and peptides. Primary structure of proteins and peptides
Squirrels– high molecular weight biopolymers built from amino acid residues. The molecular weight of proteins ranges from 6,000 to 2,000,000 Da. It is proteins that are the product of genetic information transmitted from generation to generation and carry out all life processes in the cell. These amazingly diverse polymers have some of the most important and versatile cellular functions.

Proteins can be divided:
1) by structure : simple proteins are built from amino acid residues and, upon hydrolysis, decompose only into free amino acids or their derivatives.

Complex proteins are two-component proteins that consist of a simple protein and a non-protein component called a prosthetic group. During the hydrolysis of complex proteins, in addition to free amino acids, a non-protein part or its breakdown products are formed. They may contain metal ions (metalloproteins), pigment molecules (chromoproteins), they can form complexes with other molecules (lipo-, nucleo-, glycoproteins), and also covalently bind inorganic phosphate (phosphoproteins);

2. water solubility:

– water soluble,

– salt-soluble,

– alcohol-soluble,

– insoluble;

3. functions performed : The biological functions of proteins include:

– catalytic (enzymatic),

– regulatory (the ability to regulate the rate of chemical reactions in the cell and the level of metabolism in the whole organism),

– transport (transport of substances in the body and their transfer through biomembranes),

– structural (composed of chromosomes, cytoskeleton, connective, muscle, supporting tissues),

– receptor (interaction of receptor molecules with extracellular components and initiation of a specific cellular response).

In addition, proteins perform protective, storage, toxic, contractile and other functions;

4) depending on the spatial structure:

– fibrillar (they are used by nature as a structural material),

– globular (enzymes, antibodies, some hormones, etc.).

AMINO ACIDS, THEIR PROPERTIES
Amino acids are called carboxylic acids containing an amino group and a carboxyl group. Natural amino acids are 2-aminocarboxylic acids, or α-amino acids, although there are amino acids such as β-alanine, taurine, γ-aminobutyric acid. In general, the formula for an α-amino acid looks like this:


α-amino acids have four different substituents at the 2nd carbon atom, i.e. all α-amino acids, except glycine, have an asymmetric (chiral) carbon atom and exist in the form of two enantiomers - L- And D-amino acids. Natural amino acids are L-row. D-amino acids are found in bacteria and peptide antibiotics.

All amino acids in aqueous solutions can exist in the form of bipolar ions, and their total charge depends on the pH of the medium. The pH value at which the total charge is zero is called isoelectric point. At the isoelectric point, the amino acid is a zwitterion, i.e. its amine group is protonated, and its carboxyl group is dissociated. In the neutral pH region, most amino acids are zwitterions:


Amino acids do not absorb light in the visible region of the spectrum, aromatic amino acids absorb light in the UV region of the spectrum: tryptophan and tyrosine at 280 nm, phenylalanine at 260 nm.

Proteins give a number of color reactions due to the presence of certain amino acid residues or general chemical groups. These reactions are widely used for analytical purposes. Among them, the most famous are the ninhydrin reaction, which allows for the quantitative determination of amino groups in proteins, peptides and amino acids, as well as the biuret reaction, used for the qualitative and quantitative determination of proteins and peptides. When a protein or peptide, but not an amino acid, is heated with CuSO 4 in an alkaline solution, a colored purple complex compound copper, the amount of which can be determined spectrophotometrically. Color reactions to individual amino acids are used to detect peptides containing the corresponding amino acid residues. To identify the guanidine group of arginine, the Sakaguchi reaction is used - when interacting with a-naphthol and sodium hypochlorite, guanidines in an alkaline medium give a red color. The indole ring of tryptophan can be detected by the Ehrlich reaction - a red-violet color when reacted with p-dimethylamino-benzaldehyde in H 2 SO 4. The Pauli reaction reveals histidine and tyrosine residues, which in alkaline solutions react with diazobenzene sulfonic acid, forming red-colored derivatives.

Biological role of amino acids:

1) structural elements peptides and proteins, so-called proteinogenic amino acids. Proteins contain 20 amino acids, which are encoded by the genetic code and incorporated into proteins during translation, some of which can be phosphorylated, acylated or hydroxylated;

2) structural elements of other natural compounds - coenzymes, bile acids, antibiotics;

3) signaling molecules. Some of the amino acids are neurotransmitters or precursors of neurotransmitters, hormones and histohormones;

4) the most important metabolites, for example, some amino acids are precursors of plant alkaloids, or serve as nitrogen donors, or are vital components of nutrition.

The nomenclature, molecular weight and pK values ​​of amino acids are given in Table 1.

Table 1
Nomenclature, molecular weight and pK values ​​of amino acids

Amino acids vary in solubility in water. This is due to their zwitterionic nature, as well as the ability of radicals to interact with water (hydrate). TO hydrophilic include radicals containing cationic, anionic and polar uncharged functional groups. TO hydrophobic– radicals containing alkyl or aryl groups.

Depending on polarity R-groups there are four classes of amino acids: nonpolar, polar uncharged, negatively charged and positively charged.

Non-polar amino acids include: glycine; amino acids with alkyl and aryl side chains - alanine, valine, leucine, isoleucine; tyrosine, tryptophan, phenylalanine; imino acid - proline. They strive to get into the hydrophobic environment “inside” the protein molecule (Fig. 1).

Rice. 1. Non-polar amino acids
Polar charged amino acids include: positively charged amino acids – histidine, lysine, arginine (Fig. 2); negatively charged amino acids – aspartic and glutamic acid (Fig. 3). They usually protrude outward into the protein's aqueous environment.

The remaining amino acids form the category of polar uncharged: serine and threonine (amino acids-alcohols); asparagine and glutamine (amides of aspartic and glutamic acids); cysteine ​​and methionine (sulfur-containing amino acids).

Since at neutral pH the COOH groups of glutamic and aspartic acids are completely dissociated, they are usually called glutamate And aspartate regardless of the nature of the cations present in the medium.

A number of proteins contain special amino acids that are formed by modifying ordinary amino acids after their inclusion in the polypeptide chain, for example, 4-hydroxyproline, phosphoserine, -carboxyglutamic acid, etc.

Rice. 2. Amino acids with charged side groups
All amino acids formed during the hydrolysis of proteins under fairly mild conditions exhibit optical activity, that is, the ability to rotate the plane of polarized light (with the exception of glycine).

Rice. 3. Amino acids with charged side groups
All compounds that can exist in two stereoisomeric forms, L- and D-isomers, have optical activity (Fig. 4). Proteins contain only L-amino acids.

L-alanine D-alanine
Rice. 4. Optical isomers of alanine

Glycine has no asymmetric carbon atom, while threonine and isoleucine each contain two asymmetric carbon atoms. All other amino acids have one asymmetric carbon atom.

The optically inactive form of an amino acid is called a racemate, which is an equimolar mixture D- And L-isomers, and is designated by the symbol D.L.-.

M

The amino acid numbers that make up polypeptides are called amino acid residues. Amino acid residues are connected to each other by a peptide bond (Fig. 5), in the formation of which the α-carboxyl group of one amino acid and the α-amino group of another take part.
Rice. 5. Peptide bond formation
The equilibrium of this reaction is shifted towards the formation of free amino acids rather than the peptide. Therefore, the biosynthesis of polypeptides requires catalysis and energy expenditure.

Since the dipeptide contains a reactive carboxyl and amino group, other amino acid residues can be attached to it with the help of new peptide bonds, resulting in the formation of a polypeptide - a protein.

The polypeptide chain consists of regularly repeating sections - NHCHRCO groups, forming the main chain (skeleton or backbone of the molecule), and a variable part, including characteristic side chains. R- groups of amino acid residues protrude from the peptide backbone and largely form the surface of the polymer, determining many physical and Chemical properties proteins. Free rotation in the peptide backbone is possible between the nitrogen atom of the peptide group and the neighboring α-carbon atom, as well as between the α-carbon atom and the carbon of the carbonyl group. Due to this, the linear structure can acquire a more complex spatial conformation.

An amino acid residue containing a free α-amino group is called N-terminal, and having a free -carboxyl group – WITH-end.

The structure of peptides is usually depicted with N-end.

Sometimes the terminal -amino and -carboxyl groups bind to each other, forming cyclic peptides.

Peptides differ in the number of amino acids, amino acid composition and the order of amino acid connection.

Peptide bonds are very strong, and their chemical hydrolysis requires stringent conditions: high temperature and pressure, acidic environment and long time.

In a living cell, peptide bonds can be broken by proteolytic enzymes called proteases, or peptide hydrolases.

Just like amino acids, proteins are amphoteric compounds and are charged in aqueous solutions. Each protein has its own isoelectric point - the pH value at which the positive and negative charges of the protein are completely compensated and the total charge of the molecule is zero. At pH values ​​above the isoelectric point, the protein carries a negative charge, and at pH values ​​below the isoelectric point, it carries a positive charge.
SEQUENATORS. STRATEGY AND TACTICS OF PRIMARY STRUCTURE ANALYSIS
Determining the primary structure of proteins comes down to determining the order of amino acids in the polypeptide chain. This problem is solved using the method sequencing(from English sequence-subsequence).

In principle, the primary structure of proteins can be determined by direct analysis of the amino acid sequence or by deciphering the nucleotide sequence of the corresponding genes using the genetic code. Naturally, the greatest reliability is ensured by a combination of these methods.

Sequencing itself at its current level makes it possible to determine the amino acid sequence in polypeptides whose size does not exceed several tens of amino acid residues. At the same time, the polypeptide fragments under study are much shorter than those natural proteins with which we have to deal. Therefore, preliminary cutting of the original polypeptide into short fragments is necessary. After sequencing the resulting fragments, they must be stitched back together in the original sequence.

Thus, determining the primary sequence of a protein comes down to the following main steps:

1) cleavage of the protein into several fragments of length accessible for sequencing;

2) sequencing of each of the obtained fragments;

3) assembly of the complete protein structure from the established structures of its fragments.

The study of the primary structure of a protein consists of the following stages:

– determination of its molecular weight;

– determination of specific amino acid composition (AA composition);

- definition N- And WITH-terminal amino acid residues;

– splitting of the polypeptide chain into fragments;

– cleavage of the original polypeptide chain in another way;

– separation of the resulting fragments;

– amino acid analysis of each fragment;

– establishment of the primary structure of the polypeptide, taking into account the overlapping sequences of fragments of both cleavages.

Since there is no method yet that allows one to establish the complete primary structure of a protein on an entire molecule, the polypeptide chain is subjected to specific cleavage with chemical reagents or proteolytic enzymes. The mixture of the resulting peptide fragments is separated and the amino acid composition and amino acid sequence are determined for each of them. After the structure of all fragments has been established, it is necessary to determine the order of their location in the original polypeptide chain. To do this, the protein is subjected to cleavage using another agent and a second, different set of peptide fragments is obtained, which are separated and analyzed in a similar way.

1. Determination of molecular weight (the following methods are discussed in detail in topic 3):

– by viscosity;

– by sedimentation rate (ultracentrifugation method);

– gel chromatography;

– electrophoresis in PAGE under dissociating conditions.

2. Determination of AA composition. Analysis of amino acid composition includes complete acid hydrolysis of the protein or peptide under study using 6 n. hydrochloric acid and quantitative determination of all amino acids in the hydrolyzate. Hydrolysis of the sample is carried out in sealed ampoules in a vacuum at 150°C for 6 hours. Quantitative determination of amino acids in a protein or peptide hydrolyzate is carried out using an amino acid analyzer.

3. Determination of N- and C-amino acid residues. In the polypeptide chain of a protein, on one side there is an amino acid residue carrying a free α-amino group (amino or N-terminal residue), and on the other - a residue with a free α-carboxyl group (carboxyl, or WITH-terminal residue). Analysis of terminal residues plays an important role in the process of determining the amino acid sequence of a protein. At the first stage of the study, it makes it possible to estimate the number of polypeptide chains that make up the protein molecule and the degree of homogeneity of the drug under study. In subsequent stages, using analysis N-terminal amino acid residues control the process of separation of peptide fragments.

Reactions for determining N-terminal amino acid residues:

1) one of the first methods for determining N-terminal amino acid residues was proposed by F. Sanger in 1945. When the α-amino group of a peptide or protein reacts with 2,4-dinitrofluorobenzene, a dinitrophenyl (DNP) derivative is obtained, colored yellow. Subsequent acid hydrolysis (5.7 N HCl) leads to cleavage of peptide bonds and the formation of a DNP derivative N-terminal amino acid. The DNP amino acid is extracted with ether and identified by chromatography in the presence of standards.

2) dansylation method. Greatest application for determining N-terminal residues are currently found by the dansil method, developed in 1963 by W. Gray and B. Hartley. Like the dinitrophenylation method, it is based on the introduction of a “tag” into the amino groups of the protein, which is not removed during subsequent hydrolysis. Its first step is the reaction of dansyl chloride (1-dimethylaminonaphthalene-5-sulfochloride) with the unprotonated α-amino group of a peptide or protein to form dansyl peptide (DNS peptide). At the next stage, the DNS peptide is hydrolyzed (5.7 N HC1, 105°C, 12 - 16 hours) and released N-terminal α-DNS amino acid. DNS amino acids exhibit intense fluorescence in the ultraviolet region of the spectrum (365 nm); Usually 0.1 - 0.5 nmol of the substance is sufficient for their identification.

There are a number of methods that can be used to determine how N-terminal amino acid residue and amino acid sequence. These include degradation by the Edman method and enzymatic hydrolysis by aminopeptidases. These methods will be discussed in detail below when describing the amino acid sequence of peptides.

Reactions for determining C-terminal amino acid residues:

1) among chemical methods of determination WITH-terminal amino acid residues, the hydrazinolysis method proposed by S. Akabori and the oxazolone method deserve attention. In the first of them, when a peptide or protein is heated with anhydrous hydrazine at 100 - 120°C, the peptide bonds are hydrolyzed to form amino acid hydrazides. WITH The -terminal amino acid remains as a free amino acid and can be isolated from the reaction mixture and identified (Fig. 6).

Rice. 6. Cleavage of the peptide bond with hydrazine
The method has a number of limitations. Hydrazinolysis destroys glutamine, asparagine, cysteine ​​and cystine; arginine loses its guanidine moiety to form ornithine. Serine, threonine, and glycine hydrazides are labile and easily converted into free amino acids, making the results difficult to interpret;

2) The oxazolone method, often called the tritium tag method, is based on the ability WITH-terminal amino acid residue undergoes cyclization under the influence of acetic anhydride to form oxazolone. Under alkaline conditions, the mobility of hydrogen atoms at position 4 of the oxazolone ring sharply increases and they can be easily replaced by tritium. The reaction products formed as a result of subsequent acid hydrolysis of the tritiated peptide or protein contain radioactively labeled WITH-terminal amino acid. Chromatography of the hydrolyzate and measurement of radioactivity allows identification WITH-terminal amino acid of a peptide or protein;

3) most often to determine WITH-terminal amino acid residues are enzymatically hydrolyzed by carboxypeptidases, which also allows the C-terminal amino acid sequence to be analyzed. Carboxypeptidase hydrolyzes only those peptide bonds that are formed WITH-terminal amino acid having a free α-carboxyl group. Therefore, under the action of this enzyme, amino acids are sequentially cleaved from the peptide, starting with WITH-terminal. This makes it possible to determine the relative position of alternating amino acid residues.

As a result of identification N- And WITH-terminal residues of the polypeptide provide two important reference points for determining its amino acid sequence (primary structure).

4. Fragmentation of the polypeptide chain.

Enzymatic methods. For specific breakdown of proteins at certain points, both enzymatic and chemical methods are used. Of the enzymes that catalyze the hydrolysis of proteins at specific points, trypsin and chymotrypsin are the most widely used. Trypsin catalyzes the hydrolysis of peptide bonds located after lysine and arginine residues. Chymotrypsin preferentially breaks down proteins after aromatic amino acid residues - phenylalanine, tyrosine and tryptophan. If necessary, the specificity of trypsin can be increased or changed. For example, treatment of the protein under study with citraconic anhydride leads to acylation of lysine residues. In such a modified protein, cleavage will occur only at arginine residues. Also, when studying the primary structure of proteins, proteinase, which also belongs to the class of serine proteinases, is widely used. The enzyme has two maxima of proteolytic activity at pH 4.0 and 7.8. Proteinase cleaves peptide bonds formed by the carboxyl group of glutamic acid with high yield.

Researchers also have at their disposal a large set of less specific proteolytic enzymes (pepsin, elastase, subtilisin, papain, pronase, etc.). These enzymes are mainly used for additional fragmentation of peptides. Their substrate specificity is determined by the nature of amino acid residues, not only forming a hydrolyzable bond, but also more distant along the chain.

Chemical methods.

1) among the chemical methods of protein fragmentation, the most specific and most often used is cyanogen bromide cleavage at methionine residues (Figure 7).

The reaction with cyanogen bromide results in the formation of the intermediate cyanosulfonium derivative of methionine, which spontaneously converts under acidic conditions to homoserine iminolactone, which, in turn, quickly hydrolyzes with cleavage of the imine bond. Resulting on WITH-terminus of the peptides, the homoserine lactone is further partially hydrolyzed to homoserine (HSer), resulting in each peptide fragment except WITH-terminal, exists in two forms - homoserine and homoserine lactone;

Rice. 7. Cleavage of the polypeptide chain with cyanogen bromide
2) a large number of methods have been proposed for protein cleavage at the carbonyl group of the tryptophan residue. One of the reagents used for this purpose is N-bromosuccinimide;

3) thiol-disulfide exchange reaction. Reduced glutathione, 2-mercaptoethanol, and dithiothreitol are used as reagents.

5. Determination of the sequence of peptide fragments. At this stage, the amino acid sequence in each of the peptide fragments obtained in the previous stage is established. For this purpose they usually use chemical method, designed by Per Edman. Edman cleavage boils down to the fact that only N-terminal residue of the peptide, and all other peptide bonds are not affected. After identifying the split-off N- the terminal remainder of the label is introduced into the next one, which has now become N-terminal, a residue that is cleaved off in the same way, going through the same series of reactions. Thus, by eliminating residue by residue, it is possible to determine the entire amino acid sequence of a peptide using just one sample for this purpose. In the Edman method, the peptide first reacts with phenyl isothiocyanate, which attaches to the free α-amino group N-terminal residue. Treatment of the peptide with cold dilute acid leads to elimination N-terminal residue in the form of a phenylthiohydantoin derivative, which can be identified by chromatographic methods. The rest of the peptide value after removal N-terminal residue appears intact. The operation is repeated as many times as there are residues in the peptide. In this way, the amino acid sequence of peptides containing 10 - 20 amino acid residues can be easily determined. The amino acid sequence is determined for all fragments formed during cleavage. After this there is next problem– determine the order in which the fragments were located in the original polypeptide chain.

Automatic determination of amino acid sequence . A major achievement in the field of structural studies of proteins was the creation in 1967 by P. Edman and J. Begg sequencer– a device that carries out sequential automatic elimination with high efficiency N-terminal amino acid residues using the Edman method. Modern sequencers implement various methods determining the amino acid sequence.

6. Cleavage of the original polypeptide chain in another way. To establish the order of arrangement of the resulting peptide fragments, take a new portion of the original polypeptide preparation and split it into smaller fragments in some other way, by which peptide bonds that are resistant to the action of the previous reagent are cleaved. Each of the resulting short peptides is subjected to sequential cleavage using the Edman method (the same as in the previous stage), and in this way their amino acid sequence is determined.

7. Establishment of the primary structure of the polypeptide, taking into account the overlapping sequences of fragments of both cleavages. Amino acid sequences peptide fragments obtained by two methods are compared in order to find peptides in the second set in which the sequences of individual sections would coincide with the sequences of certain sections of the peptides of the first set. Peptides from the second set with overlapping regions allow the peptide fragments obtained as a result of the first cleavage of the original polypeptide chain to be connected in the correct order.

Sometimes a second cleavage of a polypeptide into fragments is not enough to find overlapping regions for all peptides obtained after the first cleavage. In this case, a third, and sometimes a fourth, cleavage method is used to obtain a set of peptides that ensure complete overlap of all regions and establish the complete amino acid sequence in the original polypeptide chain.

All vital activity of the body is based on three pillars - self-regulation, self-renewal and self-reproduction. In the process of interacting with a changing environment, the body enters into complex relationships with it and constantly adapts to changing conditions. This is self-regulation, in which biologically active substances play an important role.

Basic biological concepts

In biology, self-regulation is understood as the body’s ability to maintain dynamic homeostasis.

Homeostasis is the relative constancy of the composition and functions of the body at all levels of organization - cellular, organ, systemic, organismal. And it is at the latter stage that the maintenance of homeostasis is ensured by biologically active substances of regulatory systems. And in the human body this is done by the following systems - nervous, endocrine and immune.

Biologically active substances secreted by the body are substances that, in small doses, can change the rate of metabolic processes, regulate metabolism, synchronize the work of all body systems, and also influence individuals of the opposite sex.

Multi-level regulation – diversity of agents of influence

Absolutely all compounds and elements that are found in the human body can be considered biologically active substances. And although they all have specific activity, performing or influencing catalytic (vitamins and enzymes), energy (carbohydrates and lipids), plastic (proteins, carbohydrates and lipids), regulatory (hormones and peptides) functions of the body. All of them are divided into exogenous and endogenous. Exogenous biologically active substances enter the body from the outside and in various ways, and all elements and substances that are part of the body are considered endogenous. Let’s focus on some substances that are important for the life of our body and give a brief description of them.

The main ones are hormones

Biologically active substances humoral regulation body - hormones that are synthesized by the endocrine and mixed glands. Their main properties are as follows:

1. They act at a distance from the place of formation.
2. Each hormone is strictly specific.
3. They are quickly synthesized and quickly inactivated.
4. The effect is achieved in very small doses.
5. They act as an intermediate link in nervous regulation.

The secretion of biologically active substances (hormones) is ensured by the human endocrine system, which includes endocrine glands (pituitary gland, pineal gland, thyroid gland, parathyroid glands, thymus, adrenal glands) and mixed secretion glands (pancreas and gonads). Each gland secretes its own hormones, which have all the listed properties and work according to the principles of interaction, hierarchy, feedback, and relationship with the external environment. All of them become biologically active substances in human blood, because this is the only way they are delivered to the interaction agents.

Mechanism of action

Biologically active substances of the glands are included in the biochemistry of life processes and affect specific cells or organs (targets). They can be of a protein nature (somatotropin, insulin, glucagon), steroidal (sex and adrenal hormones), or be derivatives of amino acids (thyroxine, triiodothyronine, norepinephrine, adrenaline). Biologically active substances of the endocrine and mixed secretion glands provide control over the stages of individual embryonic and postembryonic development. Their deficiency or excess leads to disorders varying degrees gravity. For example, a lack of biologically active substance of the pituitary gland (growth hormone) leads to the development of dwarfism, and its excess in childhood- to gigantism.

Vitamins

The existence of these low-molecular organic biologically active substances was discovered by the Russian doctor M.I. Lunin (1854-1937). These are substances that do not perform plastic functions and are not synthesized (or synthesized in very limited quantities) in the body. That is why the main source for obtaining them is food. Like hormones, vitamins exert their effects in small doses and ensure metabolic processes occur.

Vitamins are very diverse in their chemical composition and effects on the body. In our body, only vitamins B and K are synthesized by bacterial intestinal microflora, and vitamin D is synthesized by skin cells under the influence of ultraviolet radiation. We get everything else from food.

Depending on the body’s supply of these substances, the following are distinguished: pathological conditions: avitaminosis (complete absence of any vitamin), hypovitaminosis (partial deficiency) and hypervitaminosis (excess of vitamin, most often A, D, C).

Microelements

Our body contains 81 elements of the periodic table out of 92. All of them are important, but some are necessary for us in microscopic doses. These trace elements (Fe, I, Cu, Cr, Mo, Zn, Co, V, Se, Mn, As, F, Si, Li, B and Br) have long remained a mystery to scientists. Today, their role (as amplifiers of the power of the enzyme system, catalysts of metabolic processes and building elements of biologically active substances in the body) is beyond doubt. Microelement deficiency in the body leads to the formation of defective enzymes and disruption of their functions. For example, zinc deficiency leads to disturbances in the transport of carbon dioxide and disruption of the entire vascular system, the development of hypertension.

And many examples can be given, but in general, a deficiency of one or more microelements leads to delays in development and growth, disorders of hematopoiesis and the functioning of the immune system, and an imbalance in the regulatory functions of the body. And even to premature aging.

Organic and active

Among the many organic compounds that play vital role in our body, we highlight the following:

1. Amino acids, of which twelve out of twenty-one are synthesized in the body.
2. Carbohydrates. Especially glucose, without which the brain cannot function properly.
3. Organic acids. Antioxidants – ascorbic and succinic, antiseptic benzoic, heart improver – oleic.
4. Fatty acid. Everyone knows Omega 3 and 5.
5. Phytoncides, which are found in plant foods and have the ability to destroy bacteria, microorganisms and fungi.
6. Flavonoids (phenolic compounds) and alkaloids (nitrogen-containing substances) of natural origin.

Enzymes and nucleic acids

Among the biologically active substances in the blood, two more groups of organic compounds should be distinguished: enzyme complexes and adenosine triphosphate nucleic acids (ATP).

ATP is the body's universal energy currency. All metabolic processes in the cells of our body occur with the participation of these molecules. In addition, active transport of substances across cell membranes is impossible without this energy component.

Enzymes (as biological catalysts of all life processes) are also biologically active and necessary. Suffice it to say that erythrocyte hemoglobin cannot do without specific enzyme complexes and adenosine triphosphate nucleic acid, both in the fixation of oxygen and in its release.

Magic pheromones

One of the most mysterious biologically active formations are aphrodisiacs, the main goal of which is to establish communication and sexual desire. In humans, these substances are secreted in the nose and lip folds, chest, anal and genital areas, and armpits. They work in minimal quantities and are not recognized on a conscious level. The reason for this is that they enter the vomeronasal organ (located in the nasal cavity), which has a direct nervous connection with the deep structures of the brain (hypothalamus and thalamus). In addition to attracting a partner, recent studies prove that it is these volatile formations that are responsible for fertility, instincts of caring for offspring, maturity and strength of marital ties, aggressiveness or submissiveness. The male pheromone androsterone and the female copulin are quickly destroyed in the air and only work in close contact. That is why you should not particularly trust cosmetic manufacturers who actively exploit the theme of aphrodisiacs in their products.

A few words about dietary supplements

Today you cannot find a person who has not heard of dietary supplements (BAA). In fact, these are complexes of biologically active substances of various compositions that are not medicines. Dietary supplements can be pharmaceutical products - dietary supplements, vitamin complexes. Or food products additionally enriched with active ingredients not contained in this product.

The global market for dietary supplements is huge today, but the Russians are not lagging behind. Some surveys have shown that every fourth resident of Russia takes this product. At the same time, 60% of consumers use it as a supplement to food, 16% - as a source of vitamins and microelements, and 5% are sure that dietary supplements are medicines. In addition, there have been cases where, under the guise of dietary supplements such as sports nutrition and weight loss products, supplements were sold that contained psychotropic substances and narcotic drugs.

You can be a supporter or opponent of taking this product. World opinion is replete with various data on this issue. Anyway healthy image life and a varied, balanced diet will not harm your body and will eliminate doubts about taking certain nutritional supplements.

Introduction

Any living organism is an open physical and chemical system that can actively exist only under conditions of a sufficiently intense flow of chemicals necessary for the development and maintenance of structure and function. For heterotrophic organisms (animals, fungi, bacteria, protozoa, non-chlorophyll plants), chemical compounds supply all or most of the energy necessary for their life. In addition to supplying living organisms with building material and energy, they perform a variety of functions as information carriers for one organism and provide intra- and interspecific communication.

Thus, the biological activity of a chemical compound should be understood as its ability to change the functional capabilities of the body ( invitro or in vivo) or communities of organisms. This broad definition of biological activity means that almost any chemical compound or composition of compounds has some type of biological activity.

Even chemically very inert substances can have a noticeable biological effect when administered to the body in the appropriate manner.

Thus, the probability of finding a biologically active compound among all chemical compounds is close to one, but finding a chemical compound with a given type of biological activity is a rather difficult task.

Biologically active substances– chemical substances necessary to maintain the life of living organisms, which have high physiological activity at low concentrations in relation to certain groups of living organisms or their cells.

Per unit of biological activity of a chemical substance, a minimum amount of this substance is taken that can suppress the development or delay the growth of a certain number of cells, tissues of a standard strain (biotests) in a unit of nutrient medium.

Biological activity is a relative concept. The same substance may have different biological activity in relation to the same type of living organism, tissue or cell, depending on the pH value, temperature, and the presence of other biologically active substances. Needless to say, if we are talking about different biological species, then the effect of the substance can be the same, expressed in varying degrees, directly opposite or have a noticeable effect on one organism and be inert for another.

Each type of biologically active substance has its own methods for determining biological activity. Thus, for enzymes, the method for determining activity is to record the rate of substrate consumption (S) or the rate of formation of reaction products (P).

Each vitamin has its own method for determining activity (the amount of vitamin in a test sample (for example, tablets) in IU units).

Often in medical and pharmacological practice such a concept as LD 50 is used - i.e. concentration of a substance, when administered, half of the tested animals die. This is a measure of the toxicity of biologically active substances.

Classification

The simplest classification - General - divides all biologically active substances into two classes:

• endogenous
• exogenous

Endogenous substances include