Molecular Descriptors of Amino Acids for the Evaluation of the Physicochemical Parameters and Biological Activity of Peptides

Statistically significant correlation structure-activity relationships for two groups of oligopeptides (48 dipeptide fragments of analogues of inhibitors of the angiotensin-converting enzyme and 21 pentapeptide structural analogues of bradykinin) were obtained by the methods of regression analysis. Geometric, hydrophobic, and electron descriptors of the component amino acids were applied to the characteristics of the molecular structure of the peptides. The electron properties (electronegative charge, polarity of the molecules, and ability to form hydrogen bonds) were shown to have the greatest influence on the bioactivity of the studied compounds. A satisfactory fit between the calculated and experimental values of the bioactivity (log A) of the peptides proved the validity of the four-parametrical equation for the evaluation of the unknown log A values of oligopeptides on the basis of the physicochemical parameters of the participating amino acids.