COMPARISON BETWEEN THE EFFECIS OF(-)-AND (+)-GOSSYPOL ON PROTEIN KINASE C AND PROTEIN KINASE A

Protein kinase C(PKC) and protein kinase A(PKA) purified from rat liver were incubated with (-)-and (+)-gossypol. The activity of PKC was significantly inhibited in a concentration-dependent manner by both (-)-gossypol and (+)-gossypol. (-)-gossypol was found to inhibit type Ⅰ PKA, whereas the inhibitory action of (+)-gossypol for type Ⅰ PKA was less potent. Both (-)-gossypol and (+)-gossypol showed inhibition for type Ⅱ PKA only at high concentration. These results suggest that administration of gossypol might impair cellular signal transduction.