Some Properties of Photooxidized κ-casein

Abstract

Photooxidation of [kappa] -casein to the extent of 15 moles of O2 per 30,000 g oxidizes 100% of the histidine and 70% of the tryptophan. [kappa] -Casein oxidized to this degree has lost completely its ability to stabilize as-casein and it is not acted on by rennin. k -Casein to which photooxidized [kappa] -casein is added (1:1) is not precipitated by calcium ions when acted on by rennin. Photoxidation of [kappa] -casein decreases the electrophoretic mobility in starch gel at pE 8.6, but on cellulose acetate the electrophoretic mobility is greater than that of the native [kappa] -casein.