Modeling of the Peptide Release During Proteolysis of B-Lactoglobulin by Trypsin

Abstract

Prospects for predicting the fragmentation of polypeptide chains during their enzymatic hydrolysis using proteolysis models are considered. The opening of the protein substrate during proteolysis and the exposure of its internal peptide bonds for a successful enzymatic attack, the so-called demasking process, were taken into account. The two-step model of proteolysis was used, including the parameters of peptide bond demasking and hydrolysis rate constants for various peptide bonds. Herein, we presented an algorithm for calculating the concentrations of peptide fragments depending on the hydrolysis time or the degree of hydrolysis. The intermediate peptide fragments with two or one internal specific bonds were considered. The fragmentation of β-lactoglobulin (b-LG) with trypsin was predicted, and the calculated concentration curves for peptide fragments were compared with the experimental dependences of concentrations on the degree of hydrolysis. Numerical parameters characterizing the kinetic curves were proposed for the intermediate and final peptide fragments, and they were used to compare the calculated and experimental dependences. The predicted distribution of peptide fragments corresponded to the experimental data on the peptide release during proteolysis of b-LG by trypsin.