Further characterization of rennin action on kappa-casein using carboxymethylcellulose: effects of various additives on the enzymatic hydrolysis of kappa-casein.

The effects of various additives on the reaction of rennin with kappa-casein were investigated by using carboxymethylcellulose. Both urea and sodium 1-anilino-8-naphthalenesulfonate effectively inhibited rennin action at concentrations larger than 2 M and 2 mM, respectively. These reagents, however, activated the enzyme action at the lower concentrations. Both alpha S-and beta-caseins had some ranges of concentrations in which the rennin reaction was activated. Calcium chloride had an inhibitory effect on the rennin action. Neither mercaptoethanol nor KCl had any appreciable effect on the enzymatic hydrolysis of kappa-casein. These results are analyzed in terms of the association and dissociation of kappa-casein due to the presence of these additives in the reaction solutions.