[Correlation between average protein composition and amino acid properties]

Relations between amino acid properties and their averaged content in protein are discovered. Some groups of amino acids are delimited; they differ in equation parameters describing relations between amino acid properties and their content in protein. Dependence of amino acid molar content on weights of their residues in protein are hyperbolic (4 groups of amino acids with different parameters of the equations are delimited); the same relations are discovered between amino acid hydrophobicity and their molar content in protein (3 groups of amino acids are delimited). Graphs representing the relations between the content of amino acid residues in protein expressed as weight per cent and molar weights of residues and their volumes in protein look like bunches of divergent lines, each represents one group of amino acids. Delimitation of amino acids into groups correlates with ATP expenditures for their synthesis. The connection between the discovered regularities and the fact that amino acid content of averaged protein followed the Zipf law, is discussed. The role of these regularities in solving several biological problems is analysed.