Free radical-induced protein degradation of erythrocyte membrane is influenced by the localization of radical generation

We have investigated the role of the localization of free radical generatio n in erythrocyte membrane proteins degradation. The extracellular radical p roducer 2,2'-azobis(2-amidinopropane) hydrochloride induced a greater loss of band-3 protein in comparison with spectrin whereas the intracellular rad ical initiator cysteine induced the reverse effect. However, a large extent of main-chain fragmentation was observed for both proteins under the actio n of cysteine-derived radicals. The results show that the relative localiza tion of the radical generation has an important influence on the degradatio n of specific proteins of the erythrocyte membrane.