EFFECTS OF PROTEIN-KINASE-C AND PHOSPHOPROTEIN PHOSPHATASE MODULATORSON EHRLICH CELL PLASMA-MEMBRANE REDOX SYSTEM ACTIVITY

Diacyl glycerols and phorbol esters, which activate protein kinases C, stimulated Ehrlich ascites tumor cell ferricyanide reductase activity . On the contrary, selective inhibition of active protein kinases C wi th bis-indolyl maleimide did not change the rate of ferricyanide reduc tion by Ehrlich cells. Selective inhibitors of phosphoprotein phosphat ases, okadaic acid and cyclosporin A, also stimulated plasma membrane redox system. Taking all these data together, protein kinases or phosp hoprotein phosphatases seemed to be involved in the multiple and compl ex regulation of Ehrlich cell plasma membrane odor system.