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Peptides

When it comes to amino acids, proteins, fats, and carbohydrates, everyone may be quite clear, but when it comes to peptides, everyone may have a relatively limited understanding.

Today, Nutrition Sister will learn about the magical peptides with everyone.

What are the categories of it? What are the useful functions?

1. Peptides

The amino group of one amino acid can condense with the carboxyl group of another amino acid to form a peptide, and the amide group formed is called a peptide bond in protein chemistry. It is a substance that lies between amino acids and proteins.

2. Classification of Peptides

Dipeptides: Peptides formed by dehydration and condensation of two amino acids, and so on, such as tripeptides, tetrapeptides, pentapeptides, etc.

Oligopeptides: Peptides formed by dehydration and condensation of less than 10 amino acids.

Peptides: Peptides formed by dehydration and condensation of 10 or more amino acids; There is no strict difference between peptides and proteins, both are polymers of amino acids. Peptides refer to polymers with fewer amino acids, while proteins are polymers with more amino acids.

Amino acid residues: Amino acid molecules in a peptide chain that have incomplete functional groups due to dehydration and condensation are called amino acid residues.

Peptide chain: refers to a structure formed by peptide bonds connecting many amino acids. Peptide chains have two ends, N-terminal: the end of the peptide chain with a free amino group; C-terminus: The end of a peptide chain with a free carboxyl group.

Naming of Peptides

Based on the amino acid residues involved in its composition, it is determined that starting from the NH2 terminal amino acid residue of the peptide chain, it is called a certain amino acid, and always place the NH2 terminal amino acid residue on the left and the COOH terminal amino acid residue on the right, such as Ser Gly Tyr Ala Leu, which is called serine glycidyl tyrosine alanyl leucine, with the serine residue side being the NH2 terminal and the leucine residue side being the COOH terminal; Note that Leu Ala Tyr Gly Ser written in reverse is a different pentapeptide.

3. Active peptide

In addition to partial hydrolysis of proteins, various peptide segments of varying lengths can be produced in living organisms. There are also many oligopeptides or peptides that exist freely and have various special biological activities, known as active peptides.

The growth, development, cell differentiation, brain function, immunity, reproduction, aging, and pathological changes of organisms all involve active peptides;

Active peptides are the main chemical messengers for information communication within cells, between cells, and between organs; Many hormones and antibiotics belong to peptides or derivatives of peptides.

At present, it has become a hot research topic worldwide, and a large number of domestic and foreign research results have shown that bioactive peptides are bioactive substances that involve various cellular functions in organisms. Hundreds of different bioactive peptides have been found in organisms, and different bioactive peptides have different structures and physiological functions, such as antiviral, anticancer, antithrombotic, antihypertensive, immune regulation, hormone regulation, antibacterial, cholesterol lowering, and other effects. Sheep placenta is also a type of active peptide.