Biochemistry

Homeostatic proteins. Due to the presence of amine and carboxyl groups in the proteins, they have amphoteric properties. Being part of the blood buffer systems, proteins ensure the constancy of the internal environment of the human body (homeostasis). Energy proteins. During the oxidation of 1 g of protein, 4 kcal is formed. A close relationship has been established between the structure and functions of protein molecules, so before proceeding to consider their structure, it is necessary to study the biochemistry of amino acids, which are the main "building" units ("bricks") of proteins. 2.2 AMINO ACIDS Amino acids are derivatives of carboxylic acids in which one of the carbon chain hydrogens is substituted by an amino group. Depending on the position - NH 2 groups there are a-, P-, ү-, etc. amino acids. About 300 amino acids are found in nature; they can be conditionally divided into two groups: 1) free amino acids (non-proteinogenic) that are not involved in the formation of proteins; 2) proteinogenic, covalently linked to each other in the composition of peptides and proteins. Proteins include 20 a-amino acids in which the amino group -NH 2 and the carboxyl group -COOH are attached to the same a-carbon atom. The general structural formula of a-amino acids can be represented as follows: a-amino acids differ from each other in the structure and composition of the R group (side chain), which can simply be a hydrogen atom, as in glycine, or a more complex group, such as the guanidine group in arginine. NH H-C-COOH R NH H Arginine H Glycine 39