Kinetic characterization of hydrolysis of camel and bovine milk proteins by pancreatic enzymes

Abstract

As differences in protein composition between camel and bovine milk may influence their digestibility, hydrolysis of milk proteins of both species using two pancreatic serine proteases (trypsin and chymotrypsin) was studied. Caseins (CNs) were more rapidly hydrolyzed than whey proteins (WPs) because of their greater flexibility and open structures. The extent of hydrolysis by chymotrypsin of CNs in both species was significantly higher than that of hydrolysis by trypsin, which is due mainly to the greater number of potential hydrolytic sites present in the primary structures of CNs targeted by chymotrypsin than by trypsin. The extent of hydrolysis of camel WPs by each protease separately or by their mixture was less than that of bovine WPs, which can be explained by the greater stability of camel WPs compared with that of bovine WPs. The kinetic parameters ( K m and k cat) widely varied for different substrates, which results from differences in binding affinities and substrate turnovers, respectively.