α- and β-casein aggregation induced by riboflavin-sensitized photo-oxidation occurs via di-tyrosine cross-links and is oxygen concentration dependent

Type I photo-oxidation generates Trp-(TrpN) and Tyr-derived (TyrO) radicals in proteins which can dimerize producing cross-links, or alternatively react with O2. It was therefore hypothesized that the O2 concentration may have a significant effect on dye-photosensitized reactions. We studied photo-oxidation of α- and β-caseins induced by riboflavin (RF), a photosensitizing vitamin present in milk, under aerobic and anaerobic conditions....