What are peptides? Types and types of peptides. All about peptides and anti-aging cosmetics with peptides Additional peptides are not formed
These fragments are linked by a peptide bond:
This connection is called dipeptide. In this case, the dipeptide can react with one more amino acid, forming tripeptide:
Formulas peptides write so that the free amino group is on the left, and the free carboxyl group is on the right.
The structure of the peptides is written in abbreviated form (if there are many amino acid residues in the peptide). For example, vasopressin:
The same structure can be written in an abbreviated form:
Chemical properties of peptides.
The main property of peptides is their ability to hydrolyze. During hydrolysis, complete or partial destruction of the chain occurs, after which peptides of a shorter structure are formed. Complete hydrolysis occurs with prolonged heating of the peptide with concentrated hydrochloric acid.
Hydrolysis can be acid and alkaline, and can also proceed under the action of enzymes. In an acidic and alkaline environment, amino acid salts are formed, and the enzymatic process proceeds selectively, because. you can cleave specific fragments of the peptide chain.
The biological significance of peptides.
Many peptides exhibit their biological activity. The simplest peptide is glutathione, which belongs to the class of hormones. It is built from the residues of glycine, cysteine and glutamine
The human body is a complex system consisting of one hundred trillion small cells. In turn, these "bricks" of our body are made of protein molecules. This is the main building material of the body, which is also called a living nanomachine.
Peptides
Protein molecules, which each cell contains hundreds of millions, play various roles in our body. Some of them form muscle and bone tissue. Others make up the brain. Of the third, our skin is literally woven.
However, a protein molecule is not yet the smallest element of our body. It is a chain, the links of which are amino acids. Smaller parts of a protein molecule are peptides. They are elements formed from a small number of amino acids (two or more).
Distinguish between oligopeptides. These are elements, the chain of which was formed from one to two dozen amino acids. When the number of links reaches fifty, the formation of the protein itself occurs. Amino acids have a special bond with each other, called a peptide.
Protein is an indispensable building material not only for the human body. Without it, the formation of any living organism is impossible. More than a century ago, scientists developed a unique method that allows protein synthesis in the laboratory. It was possible to obtain this valuable element from cells taken from humans, plants and animals.
Peptide classification
What types of these smallest protein units exist? Allocate such:
1. Peptide hormones.
2. Neuropeptides.
3. Immunological hormones.
4. Peptide bioregulators.
Peptide hormones include pituitary and hypothalamic, thyroid and pancreatic hormones, prolactin and somatotropin, as well as glucagon. This group includes methanocyte-stimulating and adrenocorticotropic hormones.
What can be attributed to neuropeptides? Hormones, which are entrusted with the role of regulators of physiological processes. Their production occurs in the peripheral and central nervous systems.
The protective function is performed by immunological hormones, and peptide bioregulators control the work of every cell in our body.
The role of small amino acids
First of all, it consists in building our body. We already know what peptides are. These elements, in fact, represent the material from which all living organisms are composed. If failures are observed in their formation, then the body wears out and ages faster. A person becomes unable to withstand the negative effects of external factors. This leads to a variety of pathologies. Failures in the implementation of control functions in cells threaten to disrupt the functioning of organs and loss of health.
What are peptides for us? These are the elements that prevent such problems from developing:
Pathologies of blood vessels and heart;
- diseases of the digestive tract;
- obesity;
- oncology;
- diabetes.
Peptides also help cleanse the body of heavy metal salts and radionuclides that have entered it.
Information system
What are peptides for newly created protein molecules? These are a kind of information systems that write off data from the DNA matrix. It is with the help of peptides that all genetic information is transferred to newly formed protein molecules.
Scientists have found out the fact that small amino acids have a gradation according to their purpose. Each tissue and each organ has its own peptides that are not similar to others. But at the same time, the same structure of the elements of one "specialization" in various mammals has been scientifically proven. This made it possible to create drugs based on animal peptides.
Effect on the body
Scientists have conducted numerous studies, as a result of which it was established that the aging of the body, as well as the appearance of the most serious diseases in it, occurs due to disturbances in protein synthesis. If the peptides it needs are introduced into the body, then the negative process will be inhibited. The restoration of tissues and cells will begin.
In pharmacies, you can buy drugs containing peptides. Reviews of experts about these funds confirm that they make it possible to accelerate the process of cell division. At the same time, the old ones, which are already difficult to fully fulfill their functions, will be replaced by new, young and healthy ones. This, in turn, will slow down the aging process in a person and prolong his life.
Additional supply of the body with peptides will allow you to cleanse it of toxins and eliminate the deficiency of nutritional components. Such a technique will have an excellent therapeutic effect. But unlike medicines, peptides will not eliminate the symptoms of the disease. They will restore the functionality of the cells and bring them back to normal.
For those who play sports
From the important role that small chains of amino acids play in the human body, it becomes clear what peptides are for athletes. If hormonal steroid preparations were used before, now not a single doping control will miss them.
Proteins and peptides are simply necessary for athletes for the following reasons:
They activate the process of producing natural hormones (testosterone, etc.);
- accelerate muscle regeneration;
- point and very effectively restore failures in certain places of the body.
The last action I would like to note in particular. The negative impact on the body of drugs that contain conventional hormones is well known. Peptides, in contrast to them, have a positive effect on individual cells and organs. However, their action is selective.
Peptides, the effect of which is highly valued in bodybuilding, have a relatively low cost. They are permitted by law and are freely available. It is worth noting the fact that no traces remain in the body after taking peptides. This will allow you to safely pass any doping control.
What are peptides in bodybuilding? These are drugs that provide the following:
Appetite control.
- Quality of sleep.
- Bringing the emotional state back to normal.
- Increased libido.
- Strengthening immunity.
What are peptides in sports? This is a tool that allows you to improve the physical shape of the body. When they are taken, the body will not be harmed, no side effects will appear.
Peptides in cosmetology
For the healing and rejuvenation of the skin, proteins such as keratin, collagen and elastin have long been added to the composition of various creams and serums. But peptides in cosmetology are used relatively recently. In recipes for creams, serums and other products intended for the skin, this component has been used for about thirty years.
Regulatory peptides have a direct influence on the ratio of the number of cells at different stages of their maturation. These small chains of amino acids go straight to the nucleus of the cell. At the same time, peptides “monitor” and, if necessary, regulate the main stages of the genetic program. For example:
They control the rate at which stem cells divide;
- an informative DNA base is delivered, according to which cells move towards maturation;
- a certain number of receptors and enzymes are maintained at the cellular level.
What are peptides in cosmetology? These are substances that are needed in order for the cells to renew themselves faster, and the skin to rejuvenate.
Peptides can support the activity of all cellular systems at the highest level. Reviews of experts indicate that when using cosmetics that contain this valuable amino acid, the skin becomes more protected and resistant to insufficient oxygen supply. In addition, it begins to actively resist the effect that toxic substances have on it, as well as other components that destroy the epidermis.
Positive influence
Was it the first time you were advised to buy a cosmetic product that contains peptides? What it is? Customer reviews convincingly speak in favor of such funds. They reduce already appeared wrinkles, tighten and moisturize the skin. Cosmetics with peptides improve complexion. They heal the skin and give it the strength to actively fight the factors that cause aging. Peptides strengthen the contour of the face. These amazing amino acids increase the overall tone of the skin and make the collagen fibers in its layers elastic.
Regular use of products containing peptides normalizes all the recovery processes that take place in tissues and organs.
Mechanism of action
Peptides affect the body's production of genes that are responsible for cell reproduction. This function of short chain amino acids directly affects skin renewal. Peptides turn on the processes of self-healing by supplying cells with appropriate signals.
Amazing amino acids transport all active ingredients from cosmetics to the skin. And this greatly increases the efficiency of the funds used. Peptide molecules are so tiny that they easily penetrate very deep into the skin, where they carry out their stimulating functions. Moreover, they do this in accordance with the individual characteristics of tissues and human biorhythms.
If there is a violation of blood microcirculation in the layers of the skin, then the peptides will restore the walls of blood vessels. This will lead to increased blood flow and normalizes cellular nutrition. Thanks to this, the complexion will improve, spider veins and meshes will decrease.
The use of products containing peptides has a positive effect on the hair. These amino acids strengthen the follicles and promote their development. It is worth noting the fact that when using peptides, antibodies are not formed in the body. This allows us to talk about the minimum risk of allergic reactions.
Amino acids for weight loss
Peptides for weight loss are currently very popular. What are these funds? And how to use them to form a slender figure?
Preparations containing peptides for weight loss act at a slow speed. However, the process of getting rid of excess weight is quite confident. In order for the figure to change dramatically, it will take a long course of treatment for several weeks. First of all, taking the drug with peptides should speed up the metabolism in the body. Only after that, your body will begin to get rid of one extra kilogram per week. This process will become a stable weight loss, and not a stressful situation. In addition, there will be a general restructuring of the work of all systems in the direction of recovery. In this case, the body can be helped a little by including more plant foods, as well as fruits and vegetables, in the diet.
Action on the body
Means containing peptides have a complex effect. They contribute to the following:
Burning excess subcutaneous fat;
- acceleration of metabolism;
- normalization of blood glucose and cholesterol levels;
- increase in energy costs.
Functions of amino acids
The composition of drugs for weight loss includes peptides that perform a variety of work in the body. So, means for getting rid of unnecessary kilograms are created on the basis of such components:
- endorphins, which are responsible for our immunity and good mood. These peptides partially eliminate the feeling of hunger and connect the body's resource capabilities to work.
- Glucagon- a peptide that directly regulates fat and carbohydrate metabolism.
- Leptina that slows down the production of neuropeptide Y (hunger hormone). This amino acid creates the effect of accelerated saturation.
- HGH frag 176-191. The role of this peptide lies in the speedy utilization of old adipose tissues and preventing the formation of new ones.
Advantages of the method
The use of preparations made on the basis of peptides did not cause any allergic reactions during the entire period of its use. In addition, this method of losing weight not only perfectly relieves a person of obesity, but also reduces the risk of vascular and heart pathologies, as well as diabetes.
Amino acids are connected to each other by a covalent peptide bond. Its formation occurs due to the a-amino group (–NH 2) of one amino acid and the a-carboxyl (–COOH) group of another with the release of a water molecule.
As a result of the polycondensation reaction, it is possible to obtain compounds composed of many amino acid residues - polypeptides. When writing a formula for linear peptides with a known sequence of amino acid residues, they start from the N-terminus (a free a-amino group is located at the end of the peptide), using abbreviated amino acid designations. The names of peptides are made up of the names of the corresponding amino acids with the suffix - silt, starting from the N-terminal residue, the name of the C-terminal amino acid (containing a free a-carboxyl group) is retained. For example, arginyl-alanyl-glycine-glutamyl-lysine.
Each peptide contains only one free a-amino- and
a-carboxyl group, which are located on the terminal residues of amino acids. These groups and the R groups of some amino acids can be ionized, so peptides can carry charges, and can be electrically neutral (i.e., have an isoelectric point (IEP). This property of peptides is used to separate them by ion chromatography and electrophoresis. Like others compounds, peptides can enter into chemical reactions determined by the presence of groups -NH 2, -COOH, and R groups of amino acids. One of the important reactions for peptides is the hydrolysis reaction. The reaction of hydrolysis of all peptide bonds by boiling peptide solutions in the presence of a strong acid or alkali is used in determining their amino acid composition and protein composition.
Hydrolysis of peptide bonds can also be carried out by the action of certain enzymes that cleave peptide bonds selectively, with the formation of short peptides. For example, trypsin hydrolyzes bonds formed by carboxyl groups of lysine, arginine; chymotrypsin-carboxyl groups of phenylalanine, tyrosine, tryptophan. Such selective analysis is very useful in determining the amino acid sequence of proteins and peptides.
In addition to peptides formed as a result of partial hydrolysis of protein molecules, there are many peptides that occur in living organisms as free compounds.
Many natural peptides differ in their structure from proteins; such peptides are found in all types of organisms. Structurally, peptides of non-protein nature are very diverse: they differ in size, the presence of cyclic structures, branching, the presence D- and
a-amino acids and, in some individual cases, by the unique structure of the peptide bond. Based on the principle of the relationship between structure and function, the biological functions of such peptides are also very multifaceted. Let's take a look at some interesting examples.
Carnosine and Anserine. These dipeptides are found in the muscle tissues of vertebrates, including human muscles. Both contain b-alanine, a structural isomer of a-alanine.
These dipeptides serve to maintain a constant pH in muscle cells, i.e. they act as buffers, they also participate in muscle contraction, in the processes of oxidative phosphorylation, i.e. in the formation of ATP.
Glutathione(g-glutamylcysteinylglycine) is a tripeptide present in all animals, plants and microorganisms.
A distinctive structural feature of glutathione is that glutamic acid in the composition of this peptide represents a g-carboxyl (rather than an a-carboxyl group) for the formation of a peptide bond. There are two forms of glutathione, reduced (SH-glutathione) and oxidized (S-S-glutathione). The interconversion of one form to another is catalyzed by the enzyme glutathione reductase.
Only a few of the physiological functions of glutathione are currently known:
1) participation in the transport of amino acids through cell membranes;
2) maintaining the reduced state of iron (Fe +2) in hemoglobin;
3) is part of the enzyme glutathione peroxidase, which protects cells from the damaging effects of H 2 O 2.
4) participates in the detoxification of a number of compounds alien to a living cell (halogen-containing aliphatic or aromatic hydrocarbons) converts them into water-soluble compounds that are excreted from the body by the kidneys.
5) reduced glutathione protects the SH-groups of the protein from oxidation, while it itself turns into an oxidized one.
Glutathione also affects the technological properties of grain and flour. Reduced glutathione causes the restoration and rupture of disulfide bonds in the gluten protein molecule, i.e. destroys it. The dough made from such flour has poor structural and mechanical properties), it weakens, spreads out of it, you cannot get bread of normal quality.) There is a lot of glutathione in old yeast and cereal germs, which should be taken into account in baking. Reduced glutathione is able to activate proteinases (enzymes that break down proteins) of grain and flour, while the proteolysis of gluten proteins and the resulting thinning of the dough begin to proceed intensively. Glutathione contributes to the accumulation of relatively large molecular weight nitrogenous compounds in beer, which causes the formation of haze in beer and worsens its consumer properties.
Since 1981 approved for use as a low-calorie sweetener for foods aspartame (trade name). Aspartame is 200 times sweeter than sugar and is a methyl ester of a dipeptide consisting of aspartic acid and phenylalanine residues.
Mammals (including humans) produce peptides with hormonal regulatory action, and the range of application of their action and effectiveness in the body are very diverse. For example, two cyclic nonapeptides are produced by the pituitary gland. Oxytocin stimulates uterine contractions in pregnant females and milk release in lactating females. Vasopressin has a strong antidiuretic effect and is involved in the control of blood pressure. Somatostatin - one of the hormones of the hypothalamus - inhibits the synthesis of human growth hormone in the pituitary gland, which leads to a delay in the growth and development of the body.
In 1975 A group of peptides has been discovered that affect the transmission of nerve impulses. They are also called opiate peptides because their mechanism of action is similar to that of morphine and other opioids. They are present in very small amounts in both vertebrates and invertebrates. These substances have a strong analgesic effect, and are also involved in the regulation of mood and behavior.
Squirrels.
Polypeptides containing more than 51 amino acids are proteins. Proteins are part of all cells and tissues of living organisms. About 50% of the dry matter of the cell is protein.
Proteins are characterized by a certain elemental composition. Chemical analysis showed the presence in all proteins of carbon (50-55%), oxygen (21-24%), nitrogen (15-18%), hydrogen (6-7%), sulfur (0.3-2.5%) . Phosphorus, iodine, iron, copper and some other macro and microelements were also found in the composition of individual proteins, in various, often very small amounts.
Proteins (proteins, from the Greek protas - the first, most important) are high-molecular natural polymers, the molecules of which are built from amino acid residues.
The amazing thing is that all proteins in all organisms are built from the same set of 20 amino acids, each of which has no biological activity. What, then, gives the protein a specific activity, one enzymatic, the other hormonal, the third protective, etc.?
The answer is quite simple: proteins differ from each other in that each has its own characteristic amino acid sequence.
Amino acids are the alphabet of protein structure; connecting them in a different order, you can get an infinite number of sequences, and, consequently, an infinite number of different proteins that perform various biological functions.
1. Enzymatic (catalytic). In biological systems, almost all reactions are catalyzed by specific proteins - enzymes. Currently, about 300 different enzymes have been discovered, each of which serves as a catalyst for a specific biological reaction. The synthesis and decay of substances, their regulation, the transfer of chemical groups and electrons from one substance to another is carried out with the help of enzymes.
2. Construction, structural function. Proteins form the basis of the protoplasm of any living cell; in combination with lipids, they are the main structural material of all cell membranes of all organelles.
3. Motor function. Any form of movement in living nature (the work of muscles, the movement of cilia and flagella in protozoa, the movement of protoplasm in a cell, etc.) is carried out by protein structures.
4. Transport function. The transfer of various molecules, ions is carried out by specific proteins. For example, the blood protein hemoglobin carries oxygen to the tissues. The transfer of fatty acids throughout the body occurs with the participation of another blood protein, albumin.
5. Regulatory function. The regulation of carbohydrate, protein, lipid metabolism is carried out with the help of hormones, which in their structure belong to proteins (insulin) or peptides (oxytocin, vasopressin, etc.).
6. Protective - this function is performed by immunoglobulins (antibodies). They have the ability to neutralize bacteria, viruses, foreign proteins that have entered the body from the outside. The process of blood coagulation, which protects the body from its loss, is based on the transformation of a protein - fibrinogen. Keratin is the protective protein of the hair.
7. Photoreceptor proteins: for example, rhodopsin involved in visual processes.
8. Reserve proteins are used as a reserve material for feeding the developing embryo and the newborn organism - these are the proteins of the seeds of leguminous crops, albumin - egg white, milk casein. Ferretin is a protein in animal tissues that stores iron. Reserve proteins are the most important components of plant and animal food.
There are many other proteins whose functions are rather unusual. For example, monellin, a protein isolated from an African plant, has a very sweet taste. It is being studied as a non-toxic and non-obesogenic substance to be used in food instead of sugar. The blood plasma of some Antarctic fish contains a protein that has antifreeze properties.
The technology of many industries is based on the processing of proteins, changing their properties; in the leather industry, in the dressing of furs, natural silk, the production of cheeses, bread, etc.
ὀλίγος "small"); for longer sequences they are called polypeptides(from Greek. πολυ- "a lot of"); polypeptides may have non-amino acid moieties, such as carbohydrate residues, in the molecule. Proteins are usually called polypeptides containing approximately 50 amino acid residues with a molecular weight of more than 5000 (6000)-10000 daltons.To date, more than 1500 types of peptides are known, their properties have been determined, and methods of synthesis have been developed.
Pancreatic molecules of polypeptide character
- APP Avian pancreatic polypeptide
- en:HPP Human pancreatic polypeptide
Properties of peptides
Peptides are constantly synthesized in all living organisms to regulate physiological processes. The properties of peptides depend mainly on their primary structure - the sequence of amino acids, as well as on the structure of the molecule and its configuration in space (secondary structure).
Classification of peptides and the structure of the peptide chain
A peptide molecule is a sequence of amino acids: two or more amino acid residues linked together by an amide bond make up a peptide. The number of amino acids in a peptide can vary greatly. And according to their number they distinguish:
- oligopeptides - molecules containing up to ten amino acid residues; sometimes their name mentions the number of amino acids included in their composition, for example, dipeptide, tripeptide, pentapeptide, etc .;
- polypeptides are molecules that contain more than ten amino acids.
Compounds containing more than one hundred amino acid residues are commonly referred to as proteins. However, this division is arbitrary; some molecules, for example, the hormone glucagon, which contains only twenty-nine amino acids, are called protein hormones. According to the qualitative composition, they distinguish:
- homomeric peptides - compounds consisting only of amino acid residues;
- heteromeric peptides - substances that also include non-protein components.
Peptides are also divided according to the way amino acids are linked together:
- homodectic - peptides, the amino acid residues of which are connected only by peptide bonds;
- heterodetic peptides - those compounds in which, in addition to peptide bonds, there are also disulfide, ether and thioether bonds.
A chain of repeating atoms is called a peptide backbone: (-NH-CH-OC-). The (-CH-) site with an amino acid radical forms a compound (-NH-C(R1)H-OC-), called an amino acid residue. The N-terminal amino acid residue has a free α-amino group (-NH), while the C-terminal amino acid residue has a free α-carboxyl group (OC-). Peptides differ not only in amino acid composition, but also in quantity, as well as the location and connection of amino acid residues in the polypeptide chain. Example: Pro-Ser-Pro-Ala-Gis and His-Ala-Pro-Ser-Pro Despite the same quantitative and qualitative composition, these peptides have completely different properties.
Peptide bond
A peptide (amide) bond is a type of chemical bond that arises from the interaction of the α-amino group of one amino acid and the α-carboxy group of another amino acid. The amide bond is very strong and does not break spontaneously under normal cellular conditions (37°C, neutral pH). The peptide bond is destroyed by the action of special proteolytic enzymes (proteases, peptide hydrolases) on it.
Meaning
Peptide hormones and neuropeptides, for example, regulate most of the processes of the human body, including taking part in the processes of cell regeneration. Peptides of immunological action protect the body from toxins that have entered it. An adequate amount of peptides is necessary for the proper functioning of cells and tissues. However, with age and pathology, a deficiency of peptides occurs, which significantly accelerates tissue wear, which leads to aging of the whole organism. Today, the problem of peptide deficiency in the body has been learned to solve. The peptide pool of the cell is replenished with laboratory-synthesized short peptides.
Synthesis of peptides
The formation of peptides in the body occurs within a few minutes, while chemical synthesis in a laboratory is a rather lengthy process that can take several days, and the development of a synthesis technology takes several years. However, despite this, there are quite weighty arguments in favor of carrying out work on the synthesis of analogues of natural peptides. First, by chemically modifying peptides, it is possible to confirm the primary structure hypothesis. The amino acid sequences of some hormones have become known precisely through the synthesis of their analogues in the laboratory.
Secondly, synthetic peptides make it possible to study in more detail the relationship between the structure of an amino acid sequence and its activity. To elucidate the relationship between the specific structure of the peptide and its biological activity, a huge amount of work was carried out on the synthesis of more than one thousand analogues. As a result, it was possible to find out that the replacement of only one amino acid in the peptide structure can increase its biological activity several times or change its direction. A change in the length of the amino acid sequence helps to determine the location of the active centers of the peptide and the site of receptor interaction.
Thirdly, due to the modification of the original amino acid sequence, it became possible to obtain pharmacological preparations. The creation of analogues of natural peptides makes it possible to identify more "effective" configurations of molecules that enhance the biological effect or make it longer.
Fourth, the chemical synthesis of peptides is economically viable. Most therapeutic drugs would cost ten times more if they were made from a natural product.
Often active peptides are found in nature only in nanogram amounts. Plus, methods of purification and isolation of peptides from natural sources cannot completely separate the desired amino acid sequence from peptides of the opposite or other action. And in the case of specific peptides synthesized by the human body, they can only be obtained by synthesis in the laboratory.
biologically active peptides
Peptides, having high physiological activity, regulate various biological processes. According to the bioregulatory action, peptides are usually divided into several groups:
- compounds with hormonal activity (glucagon, oxytocin, vasopressin, etc.);
- substances that regulate digestive processes (gastrin, gastric inhibitory peptide, etc.);
- peptides that regulate appetite (endorphins, neuropeptide-Y, leptin, etc.);
- compounds with analgesic effect (opioid peptides);
- organic substances that regulate higher nervous activity, biochemical processes associated with the mechanisms of memory, learning, the emergence of feelings of fear, rage, etc.;
- peptides that regulate blood pressure and vascular tone (angiotensin II, bradykinin, etc.).
- peptides that have antitumor and anti-inflammatory properties (Lunasin)
However, this division is conditional, since the action of many peptides is not limited to any one direction. For example, vasopressin, in addition to vasoconstrictor and antidiuretic action, improves memory.
Peptide hormones
Peptide hormones are the most numerous and most diverse class of hormonal compounds, which are biologically active substances. Their formation occurs in specialized cells of the glandular organs, after which the active compounds enter the circulatory system for transportation to target organs. Upon reaching the goal, hormones specifically affect certain cells, interacting with the corresponding peptide bioregulators.
On the basis of the technology developed by St. Petersburg scientists, peptides with tissue-specific action were isolated from animal organs and tissues, capable of restoring metabolism at the optimal level in the cells of the tissues from which they were isolated. An important difference between these peptides is their regulatory action: when the function of the cell is suppressed, they stimulate it, and when the function is increased, they reduce it to a normal level. This made it possible to create a new class of drugs - peptide bioregulators.
The first of them, the immunomodulator thymalin, has been on the pharmaceutical market for more than 28 years and is used to restore the function of the immune system in diseases of various origins, including cancer. It was followed by epithalamin (a bioregulator of the neuroendocrine system), samprost (a drug for the treatment of diseases of the prostate gland), cortexin (a drug for the treatment of a wide range of neurological diseases), retinalamine (a drug for the treatment of degenerative-dystrophic diseases of the retina). Over 25 years of widespread use of peptide bioregulators, more than 15 million people have received them. At the same time, there were no contraindications to their use and side effects.
It has now been found that thymalin and the like are contraindicated in autoimmune diseases, since thymalin stimulates, among other things, the area of overexcited immunity. Apparently, thymalin completely lacks the suppressor function, which is extremely important in the fight against autoimmune diseases.
Peptides (from Greek πεπτός, "digestible", derived from πέσσειν, "to digest") are naturally occurring short chains of amino acid monomers linked by peptide (amide) bonds. Covalent chemical bonds are formed when the carboxyl group of one amino acid reacts with the amino group of another amino acid. The shortest peptides are dipeptides consisting of 2 amino acids connected by a single peptide bond. They are followed by tripeptides, tetrapeptides, etc. A polypeptide is a long, continuous and unbranched peptide chain. Therefore, peptides are included in the broad chemical classes of biological oligomers and polymers, along with nucleic acids, oligosaccharides and polysaccharides, etc.
Peptides differ from proteins in size, and as an arbitrary guide can be considered that they contain approximately 50 or fewer amino acids. Proteins are composed of one or more polypeptides arranged in a biologically functional pathway, often associated with ligands such as coenzymes and cofactors, or with another protein or other macromolecule (DNA, RNA, etc.), or with complex macromolecular formations. In the end, while aspects of laboratory methods applied to peptides versus polypeptides and proteins differ (e.g. specifics of electrophoresis, chromatography, etc.), the size limits that distinguish peptides from polypeptides and proteins are not absolute. : Long peptides like beta-amyloid are called proteins, while smaller proteins like insulin are considered peptides. Amino acids that have been incorporated into peptides are referred to as "residues" due to the release of either a hydrogen ion from the amine terminus or a hydroxyl ion from the carboxyl terminus, or both, as a water molecule is released upon formation of each amide bond. All peptides, with the exception of cyclic peptides, have an N-terminal and a C-terminal residue at the end of the peptide.
Peptide classes
Peptides are divided into several classes, depending on how they are produced:
Milk peptides
Two natural milk peptides are formed from the milk protein casein when it is broken down by digestive enzymes; they can also be formed from proteinases produced by lactobacilli during milk fermentation.
Ribosomal peptides
Ribosomal peptides are synthesized by translation of mRNA. They often undergo proteolysis to form the mature form. They typically function in higher organisms as hormones and signaling molecules. Some organisms produce peptides as antibiotics, such as microcins. Since they are translated, the amino acid residues involved are limited to those used by the ribosome. However, these peptides often have post-translational modifications such as phosphorylation, hydroxylation, sulfonation, palmitoylation, glycosylation, and disulfide formation. In general, they are linear, although loop-like structures have been observed. More exotic manipulations are also observed, such as the racemization of L-amino acids to D-amino acids in platypus venom.
Non-ribosomal peptides
Nonribosomal peptides are assembled by enzymes that are specific to each peptide, not by the ribosome. The most common nonribosomal peptide is glutathione, which is an integral part of the antioxidant defense of most aerobic organisms. Other nonribosomal peptides are most abundant in unicellular organisms, plants, and fungi and are synthesized by modular enzyme complexes called nonribosomal peptide synthetases. These complexes are often arranged in a similar manner, and they may contain many different modules to perform a variety of chemical manipulations on the product being developed. These peptides are often cyclic and can have highly complex cyclic structures, although linear non-ribosomal peptides are common. Since the system is closely related to machines for creating fatty acids and polyketides, hybrid compounds are often encountered. The presence of oxazoles or thiazoles often indicates that the compound is being synthesized in this manner.
Peptones
Peptones are obtained from animal milk or meat processed during proteolysis. In addition to small peptides, the resulting lyophilized material includes fats, metals, salts, vitamins, and many other biological compounds. Peptones are used in nutrient media for growing bacteria and fungi.
Peptide fragments
Peptide fragments are fragments of proteins that are used to identify or quantify a source protein. Often they are the products of enzymatic degradation performed in a laboratory on a controlled sample, but they can also be forensic or paleontological specimens that have been degraded by natural agents.
Peptides in molecular biology
Peptides have gained prominence in the field of molecular biology for several reasons. First, peptides allow the creation of peptibodies in animals without the need to purify the protein of interest. This suggests the synthesis of antigenic peptides of the regions of the protein of interest. They will then be used to generate antibodies against this protein in a rabbit or mouse. Another reason is that peptides have come to play an important role in mass spectrometry, allowing the identification of proteins of interest based on peptide masses and sequence. In this case, peptides are most often generated during gel processing after protein electrophoretic separation. Peptides have recently begun to be used in the study of the structure and function of proteins. For example, synthetic peptides can be used as probes to see where the protein-peptide interaction occurs. Inhibitory peptides are also used in clinical studies to study the effect of peptides on the inhibition of cancer proteins and other diseases. For example, one of the most promising methods involves peptides that target the luteinizing hormone releasing factor. These specific peptides act as an agonist, which means that they bind to the cell to regulate RLH receptors. The process of inhibition of cellular receptors suggests that the peptides may be useful in the treatment of prostate cancer. However, more research and experimentation is needed before the anti-cancer properties of the peptides can be considered definitive.
Peptide families
The peptide families mentioned in this section are ribosomal peptides that generally have hormonal activity. All of these peptides are synthesized by cells as longer "propeptides" or "proproteins" and are shortened before leaving the cell. They enter the bloodstream, where they perform their signaling functions.
Tachykinin peptides
Substance P
Kassinin
Neurokinin
Eledoisin
Neurokinin B
Vasoactive intestinal peptides
VIP (vasoactive intestinal peptide; PHM27)
PACAP pituitary adenylate cyclase activating peptide
PHI 27 Peptide (Peptide Histidine Isoleucine 27)
GHRH 1-24 (somatoliberin 1-24)
Glucagon
Secretin
Pancreatic polypeptide related peptides
NPY (neuropeptide Y)
PYY (peptide YY)
APP (Avian Pancreatic Polypeptide)
PPY pancreatic polypeptide
Opioid peptides
Pro-opiomelanocortin (POMC) peptides
Enkephalin pentapeptides
Prodynorphin peptides
Calcitonin peptides
Calcitonin
Other peptides
B-type natriuretic peptide (BNP) - produced in the myocardium and useful in medical diagnosis
Lactotripeptides. Lactotripeptides may lower blood pressure, although the evidence is mixed.
Notes on terminology
Length:
A polypeptide is one linear chain of many amino acids held together by amide bonds.
A protein is one or more polypeptides (more than 50 amino acids in length).
An oligopeptide consists of only a few amino acids (from two to twenty).
Amount of amino acids:
A monopeptide contains one amino acid.
A dipeptide contains two amino acids.
A tripeptide consists of three amino acids.
The tetrapeptide contains four amino acids.
The pentapeptide has five amino acids.
The hexapeptide contains six amino acids.
The heptapeptide consists of seven amino acids.
Octapeptide has eight amino acids (for example, angiotensin II).
Nonapeptide has nine amino acids (eg oxytocin).
A decapeptide has ten amino acids (for example, gonadotropin-releasing hormone and angiotensin I).
An undecapeptide (or monodecapeptide) contains eleven amino acids, a dodecapeptide (or didecapeptide) contains twelve amino acids, a tridecapeptide contains thirteen amino acids, and so on.
Icosapeptide has twenty amino acids, tricontapeptide has thirty amino acids, tetracontapeptide has forty amino acids, and so on.
Function:
A neuropeptide is a peptide that is active in combination with nervous tissue.
A lipopeptide is a peptide that has a lipid attached to it, and pepducins are lipopeptides that interact with a G-protein coupled receptor.
A peptide hormone, which is a peptide that acts like a hormone.
Proteose is a mixture of peptides obtained from the hydrolysis of proteins. The term is somewhat archaic.
Doping in sports
The term "peptide" is incorrectly or vaguely used to refer to illegal secretagogues and peptide hormones in sports doping: illegal secretagogue peptides are on the World Anti-Doping Agency's Schedule 2 (S2) Prohibited Substances and are therefore prohibited for use by professional athletes, both competitive and competitive. and non-competitive. Such peptide secretagogues have been on the WADA list of prohibited substances since at least 2008. The Australian Crime Commission (incorrectly using the term peptides) has cited alleged abuse of illegal peptide secretagogues used in Australian sport, including growth hormone stimulating peptides CJC-1295, GHRP-6, and GHSR (gene) hexarelin. There is an ongoing controversy regarding the legality of the use of peptide secretagogues in sports.
List of peptides
| 2013/12/02 20:25 | Natalia | |
| 2013/11/27 00:15 | Pavel | |
| 2013/11/27 00:19 | Pavel | |
| 2013/11/27 00:21 | Pavel | |
| 2016/08/31 21:18 | ||
| 2015/03/28 00:18 | Yana | |
| 2014/03/29 01:56 | Natalia | |
| 2013/11/26 21:00 | Pavel | |
| 2015/06/06 17:45 | Yana | |
| 2013/11/26 20:49 | Pavel | |
| 2013/11/24 15:14 | ||
| 2015/03/26 21:10 | Natalia | |
