Treatment of washed human erythrocytes for a short time (up to 2h) with 75 or 100mM 2, 2′-azo-bis(2-amidinopropane) dihydrochloride (AAPH), a water-soluble, radical-forming oxidant, induced considerable oxidation of the membrane protein SH groups, without any detectable formation of lipid peroxide from the membrane lipid. These cells became susceptible to the action of pancreatic phospholipase A
2, and the asymmetric distribution of their membrane aminophospholipids was partially lost, accompanied by a reduced activity of the aminophospholipid translocase of the membrane. In contrast, treatment of the erythrocytes with
t-butylhydroperoxide (
t-BHP), a lipid-soluble, radicalforming oxidant, caused rapid and intensive lipid peroxidation, but SH oxidation to a lesser extent than that achieved by AAPH. In these cells, the membrane phospholipid asymmetry was well maintained, although the aminophospholipid translocase activity was reduced. These results suggest that AAPH might oxidize both the aminophospholipid trans-locase of the membrane and the membrane skeletal proteins responsible for maintenance of the asymmetric phospholipid distribution, resulting in loss of the asymmetry, and that
t-BHP causes formation of peroxides from the membrane phospholipids, which might affect aminophospholipid translocase only.
抄録全体を表示