Polypeptides are proteins that have an increased condensation degree. They are widely distributed among organisms of both plant and animal origin. That is, here we are talking about components that are mandatory. They are extremely diverse, and there is no clear line between such substances and ordinary proteins. If we talk about the diversity of such substances, then it should be noted that when they are formed, at least 20 amino acids of the protenogenic type are involved in this process, and if we talk about the number of isomers, then they can be infinite.
That is why protein-type molecules have so many possibilities that are practically limitless when it comes to their multifunctionality. So, it is understandable why proteins are called the main of all life that is on Earth. Proteins are also called one of the most complex substances that nature has ever formed, and they are also very unique. Just like protein, proteins contribute to the active development of living organisms.
Speaking as specifically as possible, we are talking about substances that are biopolymers based on amino acids containing at least hundreds of amino acid type residues. Moreover, there is also a division here - there are substances that belong to a low molecular weight group, they include only a few tens of amino acid residues, there are also substances that belong to high molecular weight groups, they contain much more such residues. A polypeptide is a substance that is really very diverse in its structure and organization.
All these substances are conditionally divided into two groups, with such a division, the features of their structure are taken into account, which have a direct impact on their functionality:
The polypeptide chain is a protein structure that includes amino acids, all of which have a strong connection with peptide-type compounds. If we talk about the primary structure, then we are talking about the simplest level of the structure of a protein-type molecule. This organizational form is characterized by increased stability.
When peptide bonds begin to form in cells, the carboxyl-type group of one amino acid first of all activates, and only then does an active connection with another similar group begin. That is, polypeptide chains are characterized by constantly alternating fragments of such bonds. There are a number of specific factors that have a significant impact on the shape of the primary type structure, but their influence is not limited to this. There is an active influence on those organizations of such a chain that have the highest level.
If we talk about the features of such an organizational form, then they are as follows:
Here we are talking about a variant of chain folding in such a way that an ordered structure is organized, this becomes possible due to hydrogen bonds between groups of peptides of one chain with the same groups of another chain. If we take into account the configuration of such a structure, then it can be:
If we talk about a helical group, then this is such a protein structure that is formed in the form of a helix, which is formed without going beyond one chain of the polypeptide type. If we talk about appearance, then it is in many ways similar to the usual electric spiral, which is in a tile that runs on electricity.
As for the layered-folded structure, here the chain is distinguished by a bent configuration, its formation is carried out on the basis of hydrogen-type bonds, and here everything is limited to the limits of one section of a particular chain.
Polypeptides are analogues of protein molecules; they play an independent role in the functioning of a living organism. The structure and conformational states of polypeptides are determined by the same forces and interactions as for proteins. Polypeptides are of different origin. Polypeptides can be obtained as a result of protein cleavage (incomplete) and carry the remnants of the information embedded in it, i.e. in this case, proteinogenic acids enter into their native chain. They can be synthesized independently and have their own individual structure; in this case, they can also contain non-proteinogenic acids. It turned out that some polypeptides can include amino acids even with the D-configuration of the amino group. It turned out that their properties in the body are very diverse.
regulatory transport hormones
toxins peptides neuropeptides
antibiotics alkanoids flavor peptides
Neuropeitids. These peptides include peptides found in the brain and capable of affecting the functions of the central nervous system. The same group includes peptides of the hypothalamus and pituitary gland. Many of them regulate the behavioral responses of animals and humans, such as food satiety, thirst, sleep, learning, pleasure, physical activity, etc.
Discovered morphine-like or opioid peptides that reduce pain. They are a group of compounds similar in structure, with a common direction of action and similar in structure. Several neuropeitids, as a rule, can be derived from one precursor, by successive cleavage of fragments.
As an example, one can show the formation of a group of opioid neuropeptides ( endorphins ):
The original peptide (200 a.k.) ® b-lipotropin (91 a.k.) ® b-endorphin (31 a.k.) ® b-met-enkephalin (5 a.k.).
Hydrolysis is carried out by peptidase enzymes. Endorphins must be synthesized in the body in controlled amounts. Increased synthesis of endorphins in the body reduces learning and memory. Similar opioid peptides were found among the products of incomplete hydrolysis of milk and bread.
Another example of a neuropeitide is growth hormone - growth neurohormone. This hormone was first synthesized by K. Itakura and G. Z. Boyer, by genetic engineering. It is used in growth retardation, as well as in the treatment of diabetes.
Many of the neuropeitides have a simple structure and can be easily obtained synthetically. And this, in turn, allows you to influence the psyche of people.
transport polypeptides. Relate to natural complex compounds. The polypeptide chain is closed in a cyclic structure and has cavities of a certain size. Such cavities contain several hydroxyl groups, which, through donor-acceptor interaction, can bind those metals whose dimensions correspond to planes. The resulting secondary complex plays the role of ion transport across the membrane (ionophores).
Known ionophores corresponding to calcium ions Ca 2+ , it transports calcium through the membrane separating intra- and intercellular fluid. Another example of polytransport peptides is sodium ions Na + , it works according to the relay mechanism and has a helical shape of oxygen-containing groups. The cross section corresponds to the sodium ion Na + , and sodium is relayed from one oxygen-containing group to another.
peptide toxins. Protein-peptide nature have the most powerful toxins of microbial origin - for example, botulinum toxin produced by clostridium botulinum. It causes severe, often fatal food poisoning. Most often, the cause of poisoning with this toxin is home canning products. Toxins of snakes, scorpions, bees have a peptide nature. There are a lot of similar toxins in the pale grebe (0.4 mg per 1 g of mass with a lethal dose for humans of 5-7 mg).
Taste peptides. Peptides with pronounced taste qualities attract great attention of the food industry. The peptide sweetener aspartame is widely known; it is 200 times sweeter than sucrose. Its structure:
With improper processing of milk casein, a bitter taste heptapeptide can be formed: Arg - Gly - Pro - Fen - Ile - Val.
regulatory peptides. They can regulate various functions, for example, immunity regulators. Polypeptide cyclosporine - an antibiotic capable of inhibiting the rejection of transplanted organs and tissues.
Here it is impossible not to mention g-glutamylcysteinylglycine (glutathione) . It is found in every living cell. It regulates redox reactions according to the scheme:
Protects S-H groups of proteins from oxidation by activating thiol (cysteine) enzymes according to the scheme:
Glutathione protects ascorbic acid and other biologically active compounds from oxidation, acts as a radioprotector, and participates in the transport of amino acids through the biological membrane of the cell.
Glutathione is an essential detoxifying agent. It neutralizes mercury compounds, organophosphorus compounds, aromatic hydrocarbons, toxic peroxide compounds. Violations of the metabolism of glutathione in the body disrupts the function of the bone marrow.
The main source of glutathione is yeast, it actively affects all processes occurring during fermentation. For 4 hours of fermentation, from 80 to 300 μg / g of glutathione are released.
Peptides-hormones according to the mechanism of action, they are close to protein hormones and only formally belong to peptide hormones, these are tissue hormones. The kidney cortex contains a hormone renin , formed during the breakdown of serum a-globulin. Its functions in the body are related to the regulation of blood pressure and salt metabolism. It is released into the blood in response to a decrease in pressure and a decrease in the concentration of Na +. Another hormone collidine On the contrary, it helps to lower blood pressure. Calcitonin reduces the concentration of calcium in the blood. Glucagon , along with insulin, regulates carbohydrate metabolism, gastrin actively participates in the processes of digestion, performing many functions.
Polypeptides are responsible for the occurrence of food allergies (intolerance to certain foods - milk, egg protein, fish, meat). This is a consequence of a violation of the digestion process, which leads to incomplete breakdown of proteins, the resulting polypeptides are antigens for the human body and cause allergic reactions, since they carry partial information of the protein from which they originate. If there are few such antigens, then this is only useful for training the immune system. Too much is harmful.
The line between oligopeptides and polypeptides (the size at which a protein molecule ceases to be considered an oligopeptide and becomes a polypeptide) is rather arbitrary. Often peptides containing less than 10-20 amino acid residues are called oligopeptides, and substances with a large number of amino acid units - polypeptides. In many cases, this line is not drawn at all in the scientific literature and a small protein molecule (such as oxytocin) is referred to as a polypeptide (or simply as a peptide).
Peptides were first isolated from protein hydrolysates obtained by fermentation.
In 1953 V. Du Vigno synthesized oxytocin, the first polypeptide hormone. In 1963, based on the concept of solid-phase peptide synthesis (P. Merrifield), automatic peptide synthesizers were created. The use of methods for the synthesis of polypeptides made it possible to obtain synthetic insulin and other enzymes.
The peptide families in this section are ribosomal and typically have hormonal activity.
Opioid peptides are a group of natural and synthetic peptides similar to opiates (morphine, codeine, etc.) in their ability to bind to the body's opioid receptors. Endogenous morphine-like substances were first isolated in 1975 from the whole brain and pituitary of pigeons, guinea pigs, rats, rabbits and mice, and in 1976 fractions of such oligopeptides were found in human cerebrospinal fluid and blood. Various types of these oligopeptides are called endorphins and enkephalins. Opioid receptor ligands have also been found in many peripheral organs, tissues, and biological fluids. The presence of opioids has been shown in the hypothalamus and pituitary gland, blood plasma and cerebrospinal fluid, gastrointestinal tract, lungs, organs of the reproductive system, immunocompetent tissues, and even in the skin. Along with endorphins, the so-called exorphins or para-opioids, opioid peptides that are formed during the digestion of food, have also been found. To date, opioid receptors and their endogenous ligands have been found in almost all organs and tissues of mammals, as well as in animals of lower levels of classification up to protozoa. The main part of opioid peptides is formed by intracellular cleavage of high-molecular precursors, which leads to the formation of a number of biologically active fragments, including opioid peptides. Three such precursors have been identified and best studied: proopiomelanocortin (POMC), proenkephalin A, and prodynorphin (proenkephalin B). The composition of POMC (located mainly in the pituitary gland) includes the amino acid sequences of b-lipotropin, ACTH, a-, b- and g-melanocyte-stimulating hormones, a-, b- and g-endorphins. It has now been established that the main source of enkephalins (methionine-enkephalin and leucine-enkephalin) in the body is proenkephalin A, localized mainly in the adrenal glands. It contains 4 amino acid sequences of met-enkephalin and one leu-enkephalin, as well as a number of extended forms of met-enkephalin: methorfamide, MERGL (meth-enkephalin-Arg6-Gly7-Leu8), MERF (met-enkephalin-Arg6-Phe7) , peptide F and a group of related peptides that make up the peptide E: BAM 22, 20, 18, 12, interacting with mu-, kappa- and delta-type opioid receptors. In the structure of another proenkephalin - preproenkephalin B (or prodynorphin) - sequences of a- and b-neoendorphins, dynorphins [dynorphin 1-8, 1-17 (A), dynorphin B (rimorphin), 4kD-dynorphin] were found, which have the highest affinity for OR k-type, as well as leu-enkephalin. Radioreceptor analysis of the binding of endorphins and enkephalins to opioid receptors showed that the affinity of met- and leu-enkephalins for delta-type opioid receptors is higher than for mu-type receptors; b-endorphin has approximately the same affinity for mu- and delta-type opioid receptors, a- and g-endorphins show much less affinity for both types of receptors compared to b-endorphin. Despite the fact that met-enkephalin interacts predominantly with d-type opioid receptors, its analogs with a longer amino acid sequence - methorfamide and peptides of the BAM group (peptides from the adrenal medulla) have an opposite selectivity profile for interaction with opioid receptors (mu > kappa > delta). Most endogenous opioids can interact to some extent with several types of receptors. Thus, b-endorphin, with its N-terminal fragment, is able to interact with mu- and delta-opioid receptors, and its C-terminus with epsilon receptors. In the skin of amphibians, and then in the brain and some other organs of warm-blooded animals, the fourth precursor of OP, prodermorphin, was found, which is considered the source of dermorphin (mu-agonist) and deltorphin (delta-agonist). In the CNS, endogenous peptides specifically interacting with mu-opioid receptors were found: Tyr-Pro-Trp-Phe-NH2 and Tyr-Pro-Phe-Phe-NH2, called endomorphins, as well as the peptide nociceptin, which exerts its analgesic effect through opioid-like orphan receptors .
| organic matter | |
|---|---|
| hydrocarbons | Alkanes Alkenes Alkynes Dienes Cycloalkanes Arenes |
| Oxygen-containing | Alcohols Ethers Aldehydes Ketones Ketenes Carboxylic acids Esters Carbohydrates Fats Quinones |
| Nitrogen-containing | Amines Amides Nitro compounds Nitroso compounds Oximes Nitriles Amino acids Proteins Peptides |
| Sulfur | Mercaptans Thioethers Sulphonic acids Thioaldehydes Thioketones Thiocarboxylic acids |
| Phosphorus-containing | Phosphines Phosphonic acids Phosphinic acids Phosphonic acids Nucleic acids Nucleotides |
| organosilicon | Silanes Silazanes Siltians Siloxanes Silicones |
| Organoelement | Organogermanium · Organoboron · Organotin · Organolead · Organoaluminum · |
A polypeptide is a chemical substance consisting of a long chain of amino acids linked by peptide bonds. Polypeptides are proteins.
Fen - Ser - Ocher - Lei - Tre - Asn - Ala - Glu - Arg - Val
The genetic code is degenerate, i.e. Most amino acids are coded for by more than one codon. For example, phenylalanine (Phe) is coded for by two codons, UUU and UUC. Codons that specify the same amino acid are called synonymous codons. The degeneracy of the code, as a rule, is expressed in the fact that for codons that define the same amino acid, the first two bases are fixed, and the third position can be occupied by one of two, three, or four different bases. In particular, codons with one of the two pyrimidines (C or U) in the third position are always synonymous, while codons with one of the two purines (A or G) in the third position are only sometimes synonymous. Differences in all three positions are observed only in some cases (for example, UCG and AGU both encode Ser).
The human body is a very complex structure, which consists of a large number of cells. Each such cell contains a special type of protein. It is the building material of our body, and also performs other vital functions. Such a protein is called a "peptide".
Peptides are a type of chemical compounds that contain amino acid residues in their molecules.
The number of monomer units of amino acids in one such molecule reaches several tens. Amino acids are connected to each other through "peptide" bonds. This gave the name to the substances.
Peptides are the smallest units of protein molecules. As a rule, they are formed from 2-3 amino acids. There are also oligopeptides. They contain up to two dozen amino acids. After the number of links grows to fifty, the protein itself is formed.
Not only the human body consists of protein, but also the organisms of other living beings. More than a hundred years ago, scientists described a method that allows you to synthesize proteins in the laboratory. This process occurs due to living human cells, representatives of flora and fauna.
The characteristic properties of peptides and their effect on the human body depend on the following factors:
Today, more than 1500 varieties of these substances are known. Their influence on the human body has been studied at the proper level.
According to the functions performed, they are divided into several types:
In turn, bioregulators are divided into several types:
There is another classification - according to the size of the molecules:
The mechanism of the influence of peptides on the body is well studied. Scientists were able to prove that they are able to regulate the vital processes of cells. It is also known that the rate of aging of the body directly depends on the level of peptides in it.
The functions they perform:
What are peptides
Analyzing the benefits of amino acid chains for the body, we can conclude that they are very important for athletes. Previously used steroid drugs. But now they are banned and doping control will not allow an athlete to compete if there is even the slightest suspicion of using these medications.
Proteins and peptides are of great importance for a person involved in sports:
The last point needs more details. It is a well-known fact that drugs containing hormones have a detrimental effect on human health. And peptides, in turn, have a positive effect on the body. They direct their energy to a specific organ. This process is selective.
Another advantage of peptides is their relatively low price. They are not prohibited at the legislative level and are freely available. You should also pay attention to the fact that peptides do not leave traces in the body after their use. This allows you not to worry about possible problems before doping control.
If we talk about bodybuilding, then peptides play the following role:
We can say that peptides are very important for a person who plays sports. They help improve physical fitness, but do not harm the body, as other drugs do.
In order to improve and rejuvenate the skin, some types of protein began to be added to cosmetics:
Recently, peptides can also be found in the composition of caring cosmetics. This innovation appeared in cosmetology about 30 years ago.
Regulatory peptides have a direct effect on the ratio of the number of cells at different stages of their maturation. These chains of amino acids penetrate into the center of the nucleus. They simultaneously “monitor” and regulate important stages in the genetic program:
Customer reviews of cosmetics with peptides indicate that it reduces the number of wrinkles, tightens and moisturizes the skin of the face, makes it brighter.
Such creams heal the skin from the inside, activate its protective functions, which stops the aging process. Increase skin tone. Facial features become clearer.
Today, peptides are used not only in sports, but also for passive weight loss. They act as activity stimulants, which contributes to the effective burning of fat and the removal of excess fluid.
Peptides are natural dietary supplements and can be bought at pharmacies or sports nutrition stores. But before you decide to take such a step, you need to consult a doctor.
For fat burning, the most effective will be. They control appetite, in particular, regulate the amount of sweets consumed.
The peptide lowers the amount of the hunger hormone. The group of fat-burning peptides also includes ipamoneril, which slows down the aging process of the body, improves sleep and improves mood.
If you combine fat burning and active training, then you should pay attention to HGHFrag 176-191. Experienced athletes say that it is excellent for building muscle mass and speeds up the process of muscle recovery after a workout.
The main advantage of this method of losing weight is that the lost kilograms do not come back. Peptides do this much more effectively than any diet.
A person can remain healthy only when his cells perform their functions properly. To do this, you need to track the level of the necessary substances and replenish their stocks.
In case of a lack of peptides synthesized in the body, they can be replenished with the help of medicines and food. Scientists have proven that regular consumption of foods high in peptides prolongs life by 30%. But only under the condition of a complete rejection of bad habits and with a vision of a healthy lifestyle.
Products that contain a large amount of peptides:
There are no contraindications to the use of such food. It will be especially useful for the elderly. It is necessary to monitor the reaction of the body after a new product is introduced into the diet.
There are cases when peptides have a slight negative effect on the human body. The main features may be:
But these signs are quite minor and do not require long-term treatment. Pass within 3-7 days.
For greater effectiveness, vitamins that support antioxidants and extracts can be used in combination with peptides. When used correctly, peptides can save a person from obesity, reduce the risk of pathologies of the cardiovascular system and diabetes.
