[The study of protease primary specificity by statistical analysis of MALDI mass-spectra of proteolysis products].

Experimental verification for studying of proteolytic enzymes' primary specificity by statistical analysis of MALDI (matrix-assisted laser desorption/ionization) mass spectra of products obtained by protein substrates proteolysis was done by the use of proteinases with known substrate specificity (trypsin and glutamylendopeptidase). Proposed technique not requires direct determination of proteolysis products amino acid sequences, reliably establishes proteinases with anarrow substrate specificity and shows a relative tolerance for the presence in MALDI mass-spectra peaks of contaminants. It was shown that the pseudo-positive results exception requires the use of protein substrates series with the following averaging received statistical data.

[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).