Biochemistry

The enzymatic formation of peptides occurs in the human gastrointestinal tract during the digestion of food proteins. It begins in the stomach under the action of pepsin, gastricin and ends in the intestine with the participation of trypsin, chymotrypsin, amino and carboxypeptidases. The breakdown of short peptides is completed by di- and tripeptidases with the formation of free amino acids, which are spent on the synthesis of proteins and other active compounds. A structure has been established for many natural peptides, synthesis methods have been developed, and their role has been established. Figure 2.8 shows the physiological values and the functional role of the most common groups of peptides on which human health and the organoleptic and sanitary-hygienic properties of food products depend. Neuropeptides Vasoactives Toxins \ I / Protectors Buffers Gustatory Figure 2.8 - The most important groups of peptides Buffer peptides. In the muscles of various animals and humans, dipeptides — carnosine and anserine — were discovered that perform buffer functions due to the imidazole histidine ring that is part of them. A distinctive feature of the peptides is the presence of the p-alanine residue in them. The synthesis of dipeptide buffers is carried out without the participation of ribosomes. Carnosine and anserine are part of the extractive substances of meat. Their content in the latter reached 0.2-0.3% of the wet weight of the product. Hormone peptides. Hormones are substances of an organic nature produced by cells of the endocrine glands and entering the bloodstream to regulate the activity of individual organs and the body as a whole. The hormones oxytocin and vasopressin are secreted by the posterior pituitary gland (brain appendage). They contain 9 amino acid residues, one disulfide bond and, at the C-terminus, an amide group — CONH 2 . The regulatory function of both hormones is to stimulate the reduction of smooth muscles and secretion of milk by the mammary glands. Vasopressin is able 74