Amino acids are the main "construction material" for synthesis of specific fabric proteins, enzymes, peptide hormones and other physiologically active connections. A part of amino acids (alanine, asparagine, aspartic acid, glycine, a glutamine, glutaminic acid, proline, serine, tyrosine, cysteine) is synthesized in a human body. These are so-called replaceable amino acids. Others, belonging to irreplaceable amino acids (arginine, valine, a histidine, an isoleucine, a leucine, a lysine, methionine, threonine, tryptophane, phenylalanine), are not synthesized by an organism and arrive inside with food.
Amino acids are widely used in modern pharmacology. Being not only structural elements of proteins and other endogenous connections, they have great functional value. Some of them act as neuromediator substances (glutamic, asparaginic acids, glycine, taurine, Ag - aminobutyric acid, etc.). Phenylalanine and tyrosine are predecessors in biosynthesis of dopamine, noradrenaline, adrenaline; tryptophane - the predecessor of serotonin; a histidine - the predecessor of a histamine. Amino acids enkephalins, endorphins, dinorfinums and other neuropeptids and also the releasing factors (rileasing-factors) of a hypothalamus, hypophysis hormones, etc. are derivative.
Some amino acids (glutamic, Ag - aminobutyric, methionine, glycine, etc.) found independent application as medicines. The circle of the new medicines synthesized with use of residues of amino acids extends (see Dalargin, Captopril, Timogen, etc.).
The mixes of amino acids used as means for parenteral nutrition have special value.