Enzyme active sites: bioinformatics,architecture, and mechanisms of action

A comparative analysis of the amino acid sequences of some enzymes which comprise superfamilies of enzymes belonging to different classes was carried out. Based on the amino acid sequence alignment for enzymes belonging to different classes with the use of the information entropy as a criterion, the amino acid residues involved in the catalytic portion of the active site are demonstrated to be most conservative. The rating scale for conservativeness of amino acids in enzymes is created. Glycine and aspartic acid are the most commonly occurring conservative amino acids essential for the catalysis. The role of aspartic acid and histidine in the mechanism of molecule activation in the catalytic site is considered using hydrolases as examples. The role of glycine, proline, and cysteine in the structural organization of the active sites is discussed.