Hemin-induced membrane sulfhydryl oxidation: Possible involvement of thiyl radicals

Sublytic levels (mu M) of hemin destabilized RBC membrane as indicated by ghost fragmentation pattern using a laser viscodiffractometer. Furthermore, electron microscopic study shows that 5 mu M of hemin induced echinocytic transformation whereas higher hemin concentration (40 mu M) induced spherocytic transformation. In addition, hemin oxidized sulfhydryl groups in a dose dependent fashion and Electron Spin Resonance study suggests that such oxidation may involve a thiyl radical. Moreover, sulfhydryl compounds enhanced hemin-induced lipid peroxidation. Desferroxamine could prevent hemin-induced sulfhydryl oxidation as well as hemin-induced decrease in membrane stability. In contrast, vitamin E could effectively prevent hemin-induced Lipid peroxidation but could not prevent hemin-mediated membrane destabilization.