[Theoretical possibilities and limitations of protease primary specificity determination by statistical analysis of MALDI mass-spectra of proteolysis products].

Possibilities and limitations of method examination of proteolytic enzymes' primary specificity by statistical analysis of MALDI (matrix-assisted laser desorption/ionization) mass spectra of products obtained by protein substrates proteolysis without direct determination of their amino acid sequences were investigated theoretically. The optimum ranges given by the errors of the peptides masses measuring for the fabrication of statistical set of the events and the form of statistical data presentation were chosen. It was shown that the proposed method can be applied only for proteases with a relatively narrow primary specificity (two or three amino acids). The influence of protein substrate molecular weight and amino acid composition on the efficiency of specific to a particular protease amino acids display under statistical treatment of the set of proteolysis products masses was studied on the model of trypsin, chymotrypsin, glutamylendopeptidase, pepsin (pH 1.3).