Polypeptide is a compound formed by the connection of α -amino acids through peptide bonds, and it is also an intermediate product of protein hydrolysis. Compounds formed by dehydration and condensation of two amino acid molecules are called dipeptides, and there are also tripeptides, tetrapeptides and pentapeptides. Generally, a compound formed by dehydration and condensation of three or more amino acid molecules can be called polypeptide.
Active peptides mainly control the growth, development, immune regulation and metabolism of human body, and are in a state of balance in human body. If the number of active peptides decreases, the function of human body will change obviously. For a child, his growth,
Development becomes slow or even stops, forming a dwarf for a long time. For adults or the elderly, if they lack active peptides, their immunity will decline, and metabolic and endocrine disorders will lead to various diseases.
Health conditions, such as insomnia, emaciation or edema. Because active peptides also act on the nervous system, the human body will become dull and the brain will no longer be smart. More importantly, active peptides will decrease, which will directly lead to the gradual emergence of various parts of the human body.
Now it is aging in an all-round way, causing various diseases.
There are two kinds of peptides: bioactive peptides and synthetic peptides. Type of polypeptide:
Cytokine mimetic peptide
Screening cytokine mimetic peptides from peptide libraries by using known cytokine receptors has become a research hotspot at home and abroad in recent years. Human erythropoietin has been screen abroad,
Human thrombopoietin, human growth hormone, human nerve growth factor, interleukin and other growth factor mimetic peptides. The amino acid sequences of these mimetic peptides are different from their corresponding cytokines, but they have
Cytokine activity, and has the advantage of small molecular weight. These cytokine mimetic peptides are in preclinical or clinical research stage.
Antimicrobial active peptide
When insects are stimulated by the external environment, they produce a large number of cationic peptides with antibacterial activity. At present, more than 100 antibacterial peptides have been screened out. In vitro and in vivo experiments have confirmed that many antimicrobial peptides
Not only has strong bactericidal ability, but also can kill tumor cells. For example, antibacterial peptide D screened from silkworm shows a good application prospect and can be produced by genetic engineering technology. There are also many active peptides in snake venom, which come from snakes.
A small peptide with 13 amino acids (INKAIAALAKKLL) was isolated from the toxin, which has strong bactericidal ability against G+ and G- bacteria.
Polypeptides for cardiovascular diseases
Many Chinese herbal medicines have the functions of lowering blood pressure, reducing blood lipid and dissolving thrombus, which can be used not only as medicine, but also as health food. However, due to the uncertainty of its functional components. it should be
The use is greatly limited. It has been found that many effective components are small molecular peptides, such as active peptides processed and separated from soybeans by Chinese scientists, which can be directly absorbed through the small intestine and can prevent and treat thrombosis, hypertension and hyperlipidemia.
It can delay aging and improve the anti-tumor ability of the body. Many small peptides used for cardiovascular diseases have also been isolated from ginseng, tea, ginkgo and other plants.
Other medicinal small peptides
Small peptide drugs have made great progress in the above aspects, as well as in many other fields. For example, stiernberg and others found a combination.
Peptide-forming peptide (TP508) can promote the regeneration of wound blood vessels and accelerate the healing of deep skin wounds. Pfister et al. found that a small peptide (RTR)4 can prevent the infiltration and inhibition of corneal inflammatory cells damaged by alkali.
Inflammatory reaction. Carron et al. confirmed that the two synthetic peptides he screened could inhibit the bone absorption of osteoclasts.
Diagnostic polypeptide
Polypeptides are mainly used as antibodies in diagnostic reagents for antigen detection of viruses, cells, mycoplasma, spirochetes and other microorganisms and parasites such as cysticercosis and trypanosoma.
Antigen is more specific than natural microorganism or parasite protein antigen and easy to prepare. Therefore, the assembled detection reagent has low false negative rate and low background reaction of antibody detection, which is easy for clinical application. Now peptides are used to resist the antigen
Matching antibody detection reagents include: A, B, C, G or hepatitis virus, HIV, human cytomegalovirus, herpes simplex virus, rubella virus, Treponema pallidum, cysticercosis, trypanosoma, Lyme disease and rheumatoid disease. second-hand
Most of the polypeptide antigens were screened from the natural protein of the corresponding pathogen, and some of them were brand-new small peptides screened from the peptide library.
Active peptide species
Immunoactive peptides, neuroactive peptides and other active peptides.
Other active peptides include: cholesterol peptide, peptide for promoting mineral absorption (CPPS), enzyme regulator (such as pancreatin peptide), hormone peptide (such as growth hormone releasing factor (GRFS), albumin insulin synergistic peptide, antibacterial polypeptide (such as nisin and rubber), anticancer polypeptide (such as tumor cell necrosis factor and cyclohexene peptide) and anti-AIDS peptide (such as GLQ protein).
Characteristics of active peptides
Bioextracted peptides are very active, so they are called active peptides! Only active peptides can have a good effect on human body! However, many synthetic peptides are inactive and need to be screened. Only active peptides can be used safely by human body!
Effects on human body
Active peptides mainly control the growth, development, immune regulation and metabolism of human body, and are in a state of balance in human body. If the active peptide is reduced, the function of human body will occur.
Important changes, for children, his growth and development become slow or even stop, and over time, he becomes a dwarf. For adults or the elderly, after the lack of active peptides, his immunity will decline and his metabolism will be chaotic.
Disorder, endocrine disorder, causing various diseases, such as insomnia, weight loss or edema. Because active peptides also act on the nervous system, the human body will become dull, the brain will no longer be smart, and more importantly, active peptides.
Decrease directly leads to the gradual aging of all parts of the human body and causes various diseases.
Secretion cycle
At different ages, the secretion of various active peptides is also very different. According to the secretion, a person's life can generally be divided into:
① The period of adequate secretion (youth before the age of 25) is a period of balanced endocrine volume and vigorous immune function, and the human body is generally not prone to diseases;
② Undersecretion period (unbalanced period) (prime and middle age of 30-50 years old). During this period, if the secretion of active peptides is insufficient or unbalanced, various related sub-health States and mild disease symptoms will appear (common in people over 40 years old);
(3) Secretion deficiency period (severe deficiency period) (middle-aged and elderly people over 50 years old). If the active peptide is seriously lacking and unbalanced, it may cause very prominent aging symptoms or cause various related diseases (especially for people over 50 years old);
(4) The secretory termination period (aging period) is very short. Because the "commander-in-chief" active peptide that controls human endocrine is not secreted or secreted less, it leads to the decline of cell function, organ failure and loss, and finally leads to the end of life. polypeptide
Composition of polypeptide
-NH2 and -COOH of multi-molecular α -amino acids are condensed and dehydrated to form long-chain compounds with 10 or more peptide bonds (-CONH-). It includes a variety of compounds with certain physiological activities in human body, which can be extracted from animal tissues or synthesized artificially. Protein is a long-chain peptide formed by peptide bonds of various amino acids in a certain order, and it is a polymer compound formed by cross-linking of various secondary bonds. Protein has a complex four-level structure. Through different degrees of hydrolysis, products including peptides can be obtained: protein → proteoglycan → peptone → polypeptide → oligopeptide (2 ~ 10). This also illustrates the synthetic route of protein. Therefore, synthetic peptides can not only be used in biochemical pharmaceutical industry, but also be used to study and clarify the synthetic pathway and structure of protein.
Importance of peptide to human body
Many active substances in human body exist in the form of peptides. Peptides are involved in the growth and reproduction of hormones, nerves and cells. Their importance lies in regulating the physiological functions of various systems and cells in the body, activating related enzymes in the body, promoting the permeability of intermediate metabolic membranes, or controlling DNA transcription or influencing specific protein synthesis, and finally producing specific physiological effects. Peptide is an important substance involved in many cell functions of human body. Peptides can synthesize cells and regulate their functional activities. Peptides transmit information as neurotransmitters in human body. Peptide can be used as a transport tool in human body, which can transport various nutrients, vitamins, biotin, calcium and trace elements beneficial to human body to cells, organs and tissues. Peptide is an important physiological regulator of human body,
It can comprehensively regulate human physiological functions, enhance and exert human physiological activities, and has important biological functions. Peptides are very important for human cell activities, functional activities and life existence. But modern people make human bodies because of various factors.
The ability to synthesize peptides is greatly weakened by the loss and loss of peptides. Therefore, the modern human body lacks peptides and needs to supplement synthetic peptides. Peptide supplementation is to supplement activity, peptide supplementation is to supplement vitality, and peptide supplementation is to supplement life. (excerpt from
Professor Zou Yuandong, an expert on enzyme polypeptide, titled "Enzyme Polypeptide")