Biotechnology. Atypical aminoacids VII

This compound appeared in the last evolutionary stage of the ternary metabo lisme (abbreviated by us, M-3) and imposed itself at the beginning of the q uaternary metabolism (abbreviated by us, M-4). It was identified a group of eight pairs of alpha-aminoacids/alpha-hidroxy-acids in the structure of wh ich the unique difference is the alpha-group (i.e. -OH or -NH2). For these pairs was used the international abbreviations with N and O specifications in the parenthesis, like as ALA(N) - ALA (O). Are discussed the evolutionar y circumstances of the appearence of the typical aminoacidic structure. Are also presented the cyclic structures of the semidicetopiperasines as a lin kage step in the incipient stages of the polypeptidic evolution.