Photooxidation of β-casein

Abstract
[beta]-Casein was readily photooxidized at pH 8.6 and 37 C with the reduction or disappearance of histidine, tryptophan and tyrosine, in the order given. [beta]-Casein oxidized to the extent of 18 moles of O2/30,000 g casein was no longer precipitated by CaCl2. The binding ofCa ions to [beta]-casein was changed little or none by photooxidation. Photooxidation led to changes in UV absorption and a reduction in electrophoretic mobility in starch-gel-urea.