Federal Agency for Education

State educational institution

higher professional education "Perm State Technical University" Department of Chemistry and Biotechnology

Chemistry of biologically active compounds

Lecture notes for full-time students

specialty 070100 “Biotechnology”

Publishing house

Perm State Technical University

Compiled by: Ph.D. Biol. Sciences L.V. Anikina

Reviewer

Ph.D. chem. Sciences, Associate Professor I.A. Tolmacheva

(Perm State University)

Chemistry of biologically active substances/comp. L.V. Anikina - Perm: Perm Publishing House. state tech. University, 2009. – 109 p.

Lecture notes on the course program “Chemistry of biologically active substances” are presented.

Intended for full-time students in the direction 550800 “Chemical technology and biotechnology”, specialty 070100 “Biotechnology”.

© State Educational Institution of Higher Professional Education

"Perm State

Technical University", 2009

Introduction…………………………………………………………………………………..4

Lecture 1. Chemical components of living things…………………………………….7

Lecture 2. Carbohydrates…………………………………………………………….12

Lecture 3. Lipids………………………………………………………………..20

Lecture 4. Amino acids……………………………………………………..…35

Lecture 5. Proteins……………………………………………………………….….43

Lecture 6. Properties of proteins……………………………………………………...57

Lecture 7. Simple and complex proteins……………………………………………………...61

Lecture 8. Nucleic acids and nucleoproteins………………………….72

Lecture 9. Enzymes……………………………………………………….….85

Lecture 10. Classification of enzymes………………………………………………………... 94

Introduction

When training specialists in biotechnology, the most important basic disciplines are biochemistry, organic chemistry and the chemistry of biologically active substances. These disciplines form the fundamental basis of biotechnology, the development of which is associated with the solution of such major social problems of our time as the provision of energy, feed and food resources, environmental protection and human health.

According to the requirements of the State Standard of Higher Professional Education for the mandatory minimum content of basic educational programs in the direction 550800 “Chemical technology and biotechnology”, specialty 070100 “Biotechnology”, the discipline “Chemistry of biologically active substances” includes the following didactic units: structure and spatial organization of proteins, nucleic acids acids, carbohydrates, lipids, low molecular weight bioregulators and antibiotics; concept of enzymes, antibodies, structural proteins; enzymatic catalysis.

The purpose of teaching the discipline “Chemistry of Biologically Active Substances” is to form students’ ideas about the structure and fundamentals of functioning of biologically active substances, about enzymatic catalysis.

Lectures on the discipline “Chemistry of Biologically Active Substances” are based on students’ knowledge of the courses “General Chemistry”, “Inorganic Chemistry”, “Physical Chemistry”, “Analytical Chemistry” and “Chemistry of Coordination Compounds”. The provisions of this discipline are used for further study of the courses “Biochemistry”, “Microbiology”, “Biotechnology”.

The proposed lecture notes cover the following topics taught in the course “Chemistry of Biologically Active Substances”:

Carbohydrates, classification, chemical structure and biological role, chemical reactions characteristic of carbohydrates. Monosaccharides, disaccharides, polysaccharides.

Lipids. Classification by chemical structure, biological functions of lipids and their derivatives - vitamins, hormones, bioregulators.

Amino acids, general formula, classification and biological role. Physicochemical properties of amino acids. Proteinogenic amino acids, amino acids as precursors of biologically active molecules - coenzymes, bile acids, neurotransmitters, hormones, histohormones, alkaloids, and some antibiotics.

Proteins, elemental composition and functions of proteins. Primary structure of a protein. Characteristics of the peptide bond. Protein secondary structure: α-helix and β-sheet. Supersecondary protein structure, domain principle of protein evolution. Tertiary structure of a protein and the bonds that stabilize it. The concept of fibrillar and globular proteins. Quaternary structure of protein.

Physicochemical and biological properties of proteins. Denaturation. Chaperones.

Simple proteins: histones, protamines, prolamins, gluteins, albumins, globulins, scleroproteins, toxins.

Complex proteins: chromoproteins, metalloproteins, lipoproteins, glycoproteins, proteoglycans, nucleoproteins.

Nucleic acids, biological role in the cell. Nitrogen bases, nucleosides, nucleotides, polynucleotides of DNA and RNA. Types of RNA. Spatial structure of DNA, levels of DNA compaction in chromatin.

Enzymes as biological catalysts, their difference from non-protein catalysts. Simple and complex enzymes. The active site of the enzyme. The mechanism of action of enzymes, reduction of activation energy, formation of an enzyme-substrate complex, theory of bond deformation, acid-base and covalent catalysis. Enzyme isoforms. Multienzyme systems.

Regulation of enzyme activity at the cellular level: limited proteolysis, molecular aggregation, chemical modification, allosteric inhibition. Types of inhibition: reversible and irreversible, competitive and non-competitive. Enzyme activators and inhibitors.

Nomenclature of enzymes. International classification of enzymes.

Oxidoreductases: NAD-dependent dehydrogenases, flavin-dependent dehydrogenases, quinones, cytochrome system, oxidases.

Transferases: phosphotransferases, acyltransferases and coenzyme A, aminotransferases using pyridoxal phosphate, C 1 -transferases containing active forms of folic acid and cyanocobalamin as coenzymes, glycosyltransferases.

Hydrolases: esterases, phosphatases, glycosidases, peptidases, amidases.

Lyases: decarboxylases using thiamine pyrophosphate as a coenzyme, aldolase, hydratases, deaminases, synthases.

Isomerases: transfer of hydrogen, phosphate and acyl groups, movement of double bonds, stereoisomerases.

Ligases: the relationship between synthesis and the breakdown of ATP, carboxylase and the role of carboxybiotin, acyl-coenzyme A synthetase.

At the end of the lecture notes there is a list of literature that must be used to successfully master the course “Chemistry of Biologically Active Substances”.

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 us focus our attention 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 for the humoral regulation of the body are 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 of varying severity. 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 leads 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 pathological conditions are distinguished: 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 there are many examples, 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 a 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 acids. 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 drugs. 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. In any case, a healthy lifestyle and a varied, balanced diet will not harm your body and will eliminate doubts about taking certain nutritional supplements.

Science deals with the accumulation of knowledge and the analysis of phenomena and facts. If during the period of its inception science was united, indivisible, and this beautiful, organically characteristic feature was especially clearly manifested in the encyclopedic works of the great thinkers of antiquity, then later the time came differentiation of science.

From unitary, harmonious system of natural science how a single whole arose mathematics, physics, chemistry, biology and medicine, and in the social sciences they took shape history, philosophy, law...

This inevitable fragmentation of science, reflecting objective processes in the development of the world, continues today - appeared cybernetics, nuclear physics, polymer chemistry, oceanology, ecology, oncology and dozens of other sciences.

The spirit of the times has become narrow specialization of scientists, entire teams. Of course, this does not at all exclude the formation and education of widely educated scientists with brilliant erudition, and world science knows many examples of this.

And yet the question is logical - isn’t the possibility of understanding the holistic picture of the world around us lost in this case, isn’t the formulation of problems sometimes shallower, isn’t the search for ways to solve them artificially limited? Especially for those who are just starting their path to knowledge...

A reflection of this contradiction and a direct consequence of the laws of dialectics was counter-movement of sciences towards mutual enrichment, interaction and integration.

Appeared mathematical linguistics, chemical physics, biological chemistry...

What will be the specific and final result of this continuous search, the constant change of goals and objects of research, is still difficult to predict, but one thing is obvious - ultimately, a person will achieve progress in those areas of knowledge that just recently seemed shrouded in deep secrecy...

One striking example is the area of ​​science that lies on the border of biology and chemistry.

What unites these scientific disciplines, what is the meaning of their interaction?

After all, biology has been and, perhaps, will remain for a long time one of the most mysterious areas of knowledge, and there are many blank spots left in it.

Chemistry, on the contrary, belongs to the category of the most established, precise sciences, in which the basic laws have been clarified and tested by time.

And yet, the fact remains that chemistry and biology have been moving towards each other halfway for a long time.

When this began, it is hardly possible to establish now... We find attempts to explain the phenomena of life from the standpoint of the exact sciences among the thinkers of ancient Greek and Roman civilization; similar ideas were more clearly formulated in the works of outstanding representatives of scientific thought of the Middle Ages and the Renaissance.

By the end of the 18th century, it was reliably established that the manifestation of life is based on chemical transformations of substances, sometimes simple, and often surprisingly complex. And it is from this period that the true chronicle of the union of the two sciences begins, a chronicle rich in the most striking facts and epoch-making discoveries, the fireworks of which do not stop even today...

At the first stages it was dominated by vitalistic views who argued that chemical compounds isolated from living organisms cannot be obtained artificially, without the participation of magical life force≫.

A crushing blow to the supporters of vitalism was dealt by the work of F. Wöhler, who obtained a typical substance of animal origin - urea from ammonium cyanate. Subsequent studies have completely undermined the position of vitalism.

In the middle of the 19th century. organic chemistry is already defined as the chemistry of carbon compounds in general - be they substances of natural origin or synthetic polymers, dyes or drugs.

One by one, organic chemistry overcame the barriers standing on the way to understanding living matter.

In 1842 N. N. Zinin carried out synthesis aniline, in 1854 M. Berthelot received synthesis a number of complex organic substances, including fats.

In 1861, A. M. Butlerov was the first to synthesize a sugary substance - methylenenitane, by the end of the century, syntheses were successfully carried out a number of amino acids and fats , and the beginning of our century was marked by the first syntheses protein-like polypeptides.

This direction, which developed rapidly and fruitfully, took shape by the beginning of the 20th century. into an independent chemistry of natural compounds.

Among her brilliant victories are the decoding of the structure and synthesis of biologically important alkaloids, terpenoids, vitamins and steroids, and the peaks of her achievements in the middle of our century should be considered the complete chemical syntheses of quinine, strychnine, reserpine, penicillin and prostaglandins.

Today, dozens of sciences deal with biological problems, in which ideas and methods of biology, chemistry, physics, mathematics and other fields of knowledge are closely intertwined.

The arsenal of tools used by biology is huge. This is precisely one of the sources of its rapid progress, the basis for the reliability of its conclusions and judgments.

The paths of biology and chemistry in understanding the mechanisms of life lie side by side, and this is natural, because a living cell is a real kingdom of large and small molecules, continuously interacting, arising and disappearing...

One of the new sciences also finds its field of application here.- bioorganic chemistry.

Bioorganic chemistry is a science that studies the relationship between the structure of organic substances and their biological functions.

The objects of study are: biopolymers, vitamins, hormones, antibiotics, pheromones, signaling substances, biologically active substances of plant origin, as well as synthetic regulators of biological processes (medicines, pesticides, etc.), bioregulators and individual metabolites.

Being a section (part) of organic chemistry, this science also studies carbon compounds.

Currently there are 16 million organic substances.

Reasons for the diversity of organic substances:

1) Compounds of carbon atoms (C) can interact with each other and other elements of D.I. Mendeleev’s periodic table. In this case, chains and cycles are formed.

2) A carbon atom can be in three different hybrid states. Tetrahedral configuration of the C atom → planar configuration of the C atom.

3) Homology is the existence of substances with similar properties, where each member of the homologous series differs from the previous one by a group - CH 2 -.

4) Isomerism is the existence of substances that have the same qualitative and quantitative composition, but a different structure.

A) M. Butlerov (1861) created the theory of the structure of organic compounds, which to this day serves as the scientific basis of organic chemistry.

B) Basic principles of the theory of the structure of organic compounds:

1) atoms in molecules are connected to each other by chemical bonds in accordance with their valence;

2) atoms in molecules of organic compounds are connected to each other in a certain sequence, which determines the chemical structure of the molecule;

3) the properties of organic compounds depend not only on the number and nature of their constituent atoms, but also on the chemical structure of the molecules;

4) in molecules there is mutual influence of both atoms connected and not directly connected to each other;

5) the chemical structure of a substance can be determined by studying its chemical transformations and, conversely, its properties can be characterized by the structure of a substance.

So, the objects of study of bioorganic chemistry are:

1) biologically important natural and synthetic compounds: proteins and peptides, nucleic acids, carbohydrates, lipids,

2) mixed type biopolymers - glycoproteins, nucleoproteins, lipoproteins, glycolipids, etc.; alkaloids, terpenoids, vitamins, antibiotics, hormones, prostaglandins, growth substances, pheromones, toxins,

3) as well as synthetic drugs, pesticides, etc.

Biopolymers are high-molecular natural compounds that are the basis of all organisms. These are proteins, peptides, polysaccharides, nucleic acids (NA), lipids.

Bioregulators are compounds that chemically regulate metabolism. These are vitamins, hormones, antibiotics, alkaloids, medications, etc.

Knowledge of the structure and properties of biopolymers and bioregulators allows us to understand the essence of biological processes. Thus, the establishment of the structure of proteins and NAs made it possible to develop ideas about matrix protein biosynthesis and the role of NAs in the preservation and transmission of genetic information.

The main task of bioorganic chemistry is to elucidate the relationship between the structure and mechanism of action of compounds.

So, from what has been said, it is clear that bioorganic chemistry is a scientific field that has developed at the intersection of a number of branches of chemistry and biology.

Currently, it has become a fundamental science. 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, and a number of industries.

Main tasks:

- isolation of the studied compounds in an individual state using crystallization, distillation, various types of chromatography, electrophoresis, ultrafiltration, ultracentrifugation, countercurrent distribution, etc. p.;

- establishing a 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 rotation dispersion and circular dichroism, fast kinetics, etc. in combination with computer calculations;

- chemical synthesis And chemical modification 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 the obtained compounds in vitro and in vivo.

Solving the main problems of B. x. important for the further progress of biology. Without elucidating the structure and properties of the most important biopolymers and bioregulators, it is impossible to understand the essence of life processes, much less find ways to control such complex phenomena as:

Reproduction and transmission of hereditary characteristics,

Normal and malignant cell growth, -

Immunity, memory, nerve impulse transmission and much more.

At the same time, the study of highly specialized biologically active substances and the processes occurring with their participation can open up fundamentally new opportunities for the development of chemistry, chemical technology and engineering.

Problems whose solution is associated with research in the field of biochemistry include:

Creation of strictly specific highly active catalysts (based on the study of the structure and mechanism of action of enzymes),

Direct conversion of chemical energy into mechanical energy (based on the study of muscle contraction),

The use in technology of chemical principles of storage and transmission of information carried out in biological systems, the principles of self-regulation of multicomponent cell systems, primarily the selective permeability of biological membranes, and much more.

The listed problems lie far beyond the boundaries of B. x. itself; however, it creates the basic prerequisites for the development of these problems, providing the main supporting points for the development of biochemical research, already related to the field of molecular biology. The breadth and importance of the problems being solved, the variety of methods, and the close connection with other scientific disciplines ensured the rapid development of biochemistry.

Bioorganic chemistry emerged as an independent field in the 50s. 20th century

During the same period, this direction began to take its first steps in the Soviet Union.

The credit for this belonged to academician Mikhail Mikhailovich Shemyakin.

Then he was strongly supported by the leaders of the Academy of Sciences A.N. Nesmeyanov and N.N. Semenov, and already in 1959, the Basic Institute of the Chemistry of Natural Compounds of the USSR Academy of Sciences was created in the system of the USSR Academy of Sciences, which he headed from the moment of its creation (1959) until 1970. From 1970 to 1988, after the death of Mikhail Mikhailovich Shemyakin, the institute was headed by his student and follower, Academician Yu. A. Ovchinnikov. “Developing in the depths of organic chemistry from the very beginning of its inception as a science, it not only fed and is fed by all the ideas of organic chemistry, but also continuously enriches the latter with new ideas, new factual material of fundamental importance, new methods,” said the academician, a prominent scientist in field of organic chemistry Mikhail Mikhailovich Shemyakin (1908-1970)"

In 1963, the Department of Biochemistry, Biophysics and Chemistry of Physiologically Active Compounds of the USSR Academy of Sciences was organized. M. M. Shemyakin’s comrades in this activity, and sometimes in the struggle, were academicians A. N. Belozersky and V. A. Engelhardt; Already in 1965, Academician A. N. Belozersky founded the Interfaculty Laboratory of Bioorganic Chemistry of Moscow State University, which now bears his name.

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

Amino acids ( aminocarboxylic acids) - are bifunctional compounds that contain two reactive groups in the molecule: carbonyl (–COOH), amino group (–NH 2), α-carbon atom (in the center) and a radical (different for all α-amino acids).

Amino acids can be considered as derivatives of carboxylic acids in which one or more hydrogen atoms are replaced by amine groups.

Amino acids (except glycine) exist in two stereoisomeric forms - L and D, which rotate the plane of polarization of light to the left and to the right, respectively.

All living organisms synthesize and assimilate only L-amino acids, and D-amino acids are either indifferent or harmful to them. Natural proteins contain predominantly α-amino acids, in the molecule of which the amino group is attached to the first carbon atom (α-atom); In β-amino acids, the amino group is located at the second carbon atom.

Amino acids are monomers from which polymer molecules - proteins, or proteins - are built.

As noted earlier, almost all natural α-amino acids are optically active (with the exception of glycine) and belong to the L-series. This means that in projection Fischer, if below If you place a substituent and a carboxyl group at the top, then the amino group will be on the left.

This, of course, does not mean that all natural amino acids rotate the plane of polarized light in the same direction, since the direction of rotation is determined by the properties of the entire molecule, and not by the configuration of its asymmetric carbon atom. Most natural amino acids have an S-configuration (in the case when it contains one asymmetric carbon atom).

Some microorganisms synthesize D-series amino acids. Such amino acids are called “unnatural”.

The configuration of proteinogenic amino acids is correlated with D - glucose; this approach was proposed by E. Fischer in 1891. In Fischer’s spatial formulas, the substituents on the chiral C-2 atom occupy a position that corresponds to their absolute configuration (this was proven 60 years later).

The figure shows the spatial formulas of D- and L-alanine.

All amino acids, with the exception of glycine, are optically active due to their chiral structure.

Enantiomeric forms, or optical antipodes, have different refractive indices (circular birefringence) and different molar extinction coefficients (circular dichroism) for the left and right circularly polarized components of linearly polarized light. They rotate the plane of oscillation of linear polarized light at equal angles, but in opposite directions. The rotation occurs in such a way that both light components pass through the optically active medium at different speeds and at the same time shift in phase.

By rotation angle A, determined on a polarimeter, it is possible to determine the specific rotation [a] D.

ISOMERISM OF AMINO ACIDS

1) Isomerism of the carbon skeleton

Nonspecific metabolites .

Specific metabolites :

A). tissue hormones (parahormones);

b). true hormones.

Nonspecific metabolites- metabolic products produced by any cell in the process of vital activity and possessing biological activity (CO 2, lactic acid).

Specific metabolites- waste products produced by certain specialized types of cells, possessing biological activity and specificity of action:

A) tissue hormones- BAS produced by specialized cells have an effect mainly at the site of production.

b) true hormones- produced by endocrine glands

Participation of biologically active substances at various levels of neurohumoral regulation:

I level : local or local regulation Provided by humoral factors : mostly - nonspecific metabolites and to a lesser extent - specific metabolites (tissue hormones).

II level of regulation : regional (organ).tissue hormones.

Level III - interorgan, intersystem regulation. Humoral regulation is represented endocrine glands.

Level IV. Whole organism level. Nervous and humoral regulation are subordinated at this level of behavioral regulation.

Regulatory influence at any level is determined by a number of factors:

quantity biologically active substance;

2. quantity receptors;

3. sensitivity receptors.

In turnsensitivity depends:

A). on the functional state of the cell;

b). on the state of the microenvironment (pH, ion concentration, etc.);

V). on the duration of exposure to the disturbing factor.

Local regulation (1 level of regulation)

Wednesday is tissue fluid. Main factors:

Creative connections.

2. Nonspecific metabolites.

Creative connections- exchange between cells of macromolecules that carry information about cellular processes, allowing tissue cells to function cooperatively. This is one of the most evolutionarily old methods of regulation.

Keylons- substances that provide creative connections. They are represented by simple proteins or glycoproteins that affect cell division and DNA synthesis. Violation of creative connections may underlie a number of diseases (tumor growth) as well as the aging process.

Nonspecific metabolites - CO 2, lactic acid - act at the site of formation on neighboring groups of cells.

Regional (organ) regulation (2nd level of regulation)

1. nonspecific metabolites,

2. specific metabolites (tissue hormones).

Tissue hormone system

Substance	Place of generation	Effect
Seratonin	intestinal mucosa (enterochromaffin tissue), brain, platelets	CNS mediator, vasoconstrictor effect, vascular-platelet hemostasis
Prostaglandins	derivative of arachidonic and linolenic acid, body tissue	Vasomotor effect, and dilator and constrictor effect, enhances uterine contractions, enhances the excretion of water and sodium, reduces the secretion of enzymes and HCl by the stomach
Bradykinin	Peptide, blood plasma, salivary glands, lungs	vasodilator effect, increases vascular permeability
Acetylcholine	brain, ganglia, neuromuscular junctions	relaxes the smooth muscles of blood vessels, reduces heart contractions
Histamine	histidine derivative, stomach and intestines, skin, mast cells, basophils	mediator of pain receptors, dilates microvessels, increases the secretion of gastric glands
Endorphins, enkephalins	brain	analgesic and adaptive effects
Gastrointestinal hormones	produced in various parts of the gastrointestinal tract	participate in the regulation of secretion, motility and absorption processes

Substances (abbreviated as BAS) are special chemical substances that, at low concentrations, have high activity towards certain groups of organisms (humans, plants, animals, fungi) or certain groups of cells. BAS are used in medicine and as a disease prevention, as well as to maintain normal life functions.

Biologically active substances are:

1. Alkaloids are nitrogen-containing in nature. Typically of plant origin. They have basic properties. Insoluble in water, they form various salts with acids. They have good physiological activity. In large doses these are strong poisons, in small doses they are medicines (medicines “Atropine”, “Papaverine”, “Ephedrine”).

2. Vitamins are a special group of organic compounds that are vital for animals and humans for good metabolism and full functioning. Many of the vitamins take part in the formation of necessary enzymes and inhibit or accelerate the activity of certain enzyme systems. Vitamins are also used as food (they are included in their composition). Some vitamins enter the body with food, others are formed by microbes in the intestines, and others appear as a result of synthesis from fat-like substances under the influence of ultraviolet radiation. A lack of vitamins can lead to various metabolic disorders. A disease that occurs as a result of a low intake of vitamins in the body is called vitamin deficiency. A deficiency - and an excessive amount - is hypervitaminosis.

3. Glycosides are compounds of organic nature. They have a wide variety of effects. Glycoside molecules consist of two important parts: a non-sugar part (aglycone or genin) and a sugar part (glycone). In medicine, it is used to treat diseases of the heart and blood vessels, as an antimicrobial and expectorant. Glycosides also relieve mental and physical fatigue, disinfect the urinary tract, calm the central nervous system, improve digestion and increase appetite.

4. Glycolalkaloids are biologically active substances related to glycosides. The following medications can be obtained from them: “Cortisone”, “Hydrocortisone” and others.

5. (another name is tannids) are capable of precipitating proteins, mucus, adhesives, and alkaloids. For this reason, they are incompatible with these substances in medications. With proteins they form albuminates (an anti-inflammatory agent).

6. Fatty oils are fatty acids or trihydric alcohol. Some fatty acids are involved in the removal of cholesterol from the body.

7. Coumarins are biologically active substances based on isocoumarin or coumarin. This group also includes pyranocoumarins and furocoumarins. Some coumarins have an antispasmodic effect, others exhibit capillary-strengthening activity. There are also coumarins with anthelmintic, diuretic, curare-like, antimicrobial, analgesic and other effects.

8. Microelements, like vitamins, are also added to biologically active food supplements. They are part of vitamins, hormones, pigments, enzymes, form chemical compounds with proteins, accumulate in tissues and organs, in endocrine glands. The following microelements are important for humans: boron, nickel, zinc, cobalt, molybdenum, lead, fluorine, selenium, copper, manganese.

There are other biologically active substances: (there are volatile and non-volatile), pectin substances, pigments (another name is coloring substances), steroids, carotenoids, flavonoids, phytoncides, ecdysones, essential oils.