What are peptides? Do they do anything? How many types are there?
When it comes to amino acids, proteins, fats and sugars, you may know them well, but you may not know much about peptides.
Today, I would like to tell you about the amazing peptides.
What types of peptides are they? What are their functions?
The amino group of an amino acid and the carboxyl group of another amino acid can be condensed to form a peptide, the amide group formed is called a peptide bond in protein chemistry. It is a substance between amino acid and protein.
2、Classification of peptides
Dipeptide: a peptide formed by the dehydration condensation of two amino acids, and so on, tripeptide, tetrapeptide, pentapeptide, etc.
Oligopeptide: a peptide formed by the dehydration and condensation of less than 10 amino acids.
Polypeptide: peptide formed by the dehydration condensation of 10 or more amino acids; there is no strict difference between polypeptide and protein, both are polymers of amino acids, polypeptide is a polymorph containing a smaller number of amino acids and protein is a polymorph containing a larger number of amino acids.
Amino acid residues: amino acid molecules in a peptide chain that have incomplete groups due to dehydration and condensation are called amino acid residues.
Polypeptide chain: A structure in which many amino acids are linked by peptide bonds. The polypeptide chain has two ends, N-terminal: the end of the polypeptide chain with a free amino group; C-terminal: the end of the polypeptide chain with a free carboxyl group.
Naming of peptides
According to the amino acid residues involved in its composition, it is prescribed to start from the NH2-terminal amino acid residue of the peptide chain, called a certain amino acyl a certain amino acyl ...... a certain amino acid, and always put the NH2-terminal amino acid residue on the left and the COOH-terminal amino acid residue on the right, for example Ser-Gly-Tyr-Ala -Leu, called serinylglycyltyrosylalanylleucine, with the NH2-terminal on the side of the serine residue and the COOH-terminal on the side of the leucine residue; note that Leu-Ala-Tyr-Gly-Ser, written in reverse, is a different pentapeptide.
In addition to the partial hydrolysis of proteins in living organisms can produce a variety of peptides of different lengths, there are many oligopeptides or peptides free existence, with a variety of special biological activity, called active peptides.
The growth, development, cell differentiation, brain function, immunity, reproduction, ageing and pathology of organisms all involve active peptides.
Active peptides are the main chemical messengers for intra-cellular, inter-cellular and inter-organ information communication; many hormones and antibiotics are peptides or peptide derivatives.
At present, it has become a hot spot for research all over the world, and a large number of domestic and foreign research results show that: bioactive peptides are bioactive substances involving a variety of cellular functions in living organisms, hundreds of them have been found in living organisms, and different bioactive peptides have different structures and physiological functions, such as anti-virus, anti-cancer, anti-thrombosis, anti-hypertension, immunomodulation, hormone regulation, anti-bacterial, cholesterol-lowering and other effects. Sheep placenta is also one of the active peptides.