Mechanism of Inactivation of Trypsin by Photo-chemical Reaction of Xanthene Dyes

Trypsin-inactivating xanthene dyes such as phloxine, erythrosine, rose bengale and eosine have a photo-labile α-substituted carbonyl group in each structure. The photo-effects of bromine and iodine to trypsin were investigated. Iodine partially inhibited (40%) the enzymatic activity in the dark. Under the light condition, the inactivation was occurred so rapidly and extremely. It was assumed that some photo-excited state of halogen atom would be necessary for the inactivation of trypsin.