Effect of Succinylation on the Proteolysis of Food Proteins

Casein, bovine serum albumin and soy globulin were succinylated and used as substrates, in both forms, for initial velocity studies of proteolysis by α-chymotrypsin and pepsin. Succinylation resulted in modification of at least 91% of the free amine groups of the proteins. Proteolysis was determined by fluorometrically monitoring the appearance of amine groups. Kinetic constants were estimated by the direct equation plot using FORTRAN programs. Succinylation enhanced the initial proteolysis of all substrates by either enzyme as evidenced by an increased maximum velocity and decreased Michaelis constant for the modified substrates. Modification of casein caused the most pronounced differences in rates of proteolysis, resulting in the largest change in kinetic constants for pepsin and the smallest change for α-chymotrypsin.