IDENTIFICATION OF PHORBOL-MYRISTATE ACETATE STIMULATED KINASE IN ZEA-MAYS

Following DEAE-Sephacel and affinity chromatography a highly enriched lipid stimulated kinase activity could be recovered with a purificatio n fold of 1725. The peak kinase activity fraction eluted with 0.1 mM c alcium from phosphatidyl serine affinity chromatography showed a major protein of 70 kD and a minor band of 55 kD molecular weight and showe d kinase activity that was stimulated by phorbol myristate acetate in the presence of phosphatidylserine and calcium. The optimum requiremen t was 2.5 x 10(-6) M, 1.25 x 10(-4) M, 1 x 10(-4) M, and 1.7 x 10(-6) M for phorbol myristate acetate, phosphatidyl serine, oleyl acetyl gly cerol and free calcium respectively. The kinase activity was inhibited by H-7 and staurosporine. The binding of [H-3]-phorbol myristate acet ate was associated with purified fraction as resolved by gel electroph oresis and the kinase activity was also precipitated by animal protein kinase C antibodies. The present data give strong evidence for the pr esence of phorbol myristate acetate stimulated kinase in plants.