Degradation of Casein Components by Acid Protease of Bovine Milk

Abstract

Degradation of αs1-, β-, and κ-caseins by an acid protease of bovine milk was studied by disc and urea-sodium dodecylsulfate electrophoresis. The acid protease converted αs1-casein into a fragment, with a mobility equal in both disc and urea-sodium dodecylsulfate electrophoresis to that of as αs1-1 casein produced by the action of chymosin. New bands, with mobilities equal in disc and urea-sodium dodecylsulfate electrophoresis to those of β-l and β-II fractions produced by chymosin action, appeared by the action of acid protease on β-casein. Furthermore, a para-κ-casein-like protein was formed from κ-casein by the acid protease. However, the para-κ -casein-like protein was formed much slower by the acid protease than was para-κ-casein by chymosin. © 1980, American Dairy Science Association. All rights reserved.