Susceptibility of kappa-casein components to various proteases.
In order to clarify the function of the carbohydrate moiety of bovine kappa-casein, kappa-casein components having different carbohydrate contents were prepared by DEAE-cellulose chromatography. Five adsorbed fractions so obtained had an identical peptide chain and contained carbohydrate moieties of increasing size in the order of components P-2, P-3, P-4, P-5 and P-6. The subsceptibility of kappa-casein components, having different carbohydrate contents, to various proteases was examined. kappa-Casein components were subjected to calf rennin  [chymosin; EC 3.4.23.4], bovine trypsin [EC 3.4.21.4], alpha-chymotrypsin [EC 3.4.21.1], pronase [EC 3.4.24.4] and human plasmin [EC 3.4.21.7]. The component containing a larger carbohydrate moiety was less susceptible to hydrolysis than the component containing a smaller carbohydrate moiety. Rennin, trypsin, alpha-chymotrypsin and pronase hydrolyzed each component with a different reaction rate. On the contrary, human plasmin hydrolyzed component P-2, but did not hydrolyze component P-5. These results indicate that the carbohydrate moiety of kappa-casein components to various proteases.
D050260:Carbohydrate Metabolism; D002364:Caseins / Q000378:metabolism*; D002918:Chymotrypsin / Q000378:metabolism; D005341:Fibrinolysin / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism*; D011402:Pronase / Q000378:metabolism; D012083:Renin / Q000378:metabolism; D013329:Structure-Activity Relationship; D014357:Trypsin / Q000378:metabolism
D002364:Caseins; D010447:Peptide Hydrolases; D002918:Chymotrypsin; D014357:Trypsin; D005341:Fibrinolysin; D012083:Renin; D011402:Pronase