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KMID : 0376219870240020259
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Chonnam Medical Journal
1987 Volume.24 No. 2 p.259 ~ p.267
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Inhibition of Erythrocyte Membrane-Bound Enzymes by Active Oxygen Species
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李民化/Lee, Min-wha
梁誠烈/崔湖鎭/朴昞柱/Yang, Seung-yeul/Chay, Ho-jin/Park, Byung-ju
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Abstract
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Oxygen free radicals were generated by the autooxidation of dihydroxyfu￢maric acid (DHF) and by the photolysis of phenazine methosulfate (PMS), and their effects on Na+, K+-ATPase and acetylcholinesterase of rabbit erythrocyte membranes as well as on the membrane lipid peroxidation were studied.
The oxygen free radical-generating capacity of DHF system was found to be approximately 30 times as powerful as that of PMS system as determined by the associated oxygen consumption rate. However, the membrane lipid peroxidation, measured by thiobarbituric acid reaction, and loss of the Na+, K+-ATPase were caused more markedly by PMS than by DHF. The inhibition of the Na+, K+-ATPase by PMS and DHF was not affected by superoxide dismutase (SOD) and catalase, but partially prevented by hydroxyl radical scavengers such as mannitol and thiourea.
Although the membrane acetylcholinesterase was not affected by DHF, it was markedly inhibited by PMS in a dose-dependent manner. The PMS￢inhibition of the acetylcholinesterase was partially prevented by thiourea, but not by SOD, catalase, and even mannitol.
These results suggest that the externally added oxygen free radical genera￢tors enter the erythrocyte membrane in a lipid solubility-dependent manner and generate hydroxyl radicals there. The hydroxyl radicals thus generated cause an oxidative damage to the membrane-bound enzymes, leading even-tually to the loss of the enzyme activities with the associated increase in the membrane lipid peroxidation.
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