Cyclic AMP-dependent and independent protein kinases in Ascaridia galli.

The occurrence of multiple protein kinases, distinguished with respect to molecular weight and preference for acceptor proteins, was demonstrated in Ascaridia galli. The molecular weights of the cyclic AMP-dependent protein kinase and of phosvitin kinase I and II - both independent of cyclic AMP-were determined to be 160000, greater than 200000 and 40000, respectively. The cyclic AMP-dependent protein kinase preferred histones and kemptide as acceptor substrates; stimulation of enzyme activity was up to 4-fold by cyclic AMP. The activities of phosvitin kinase I and II were found to be effectively inhibited by suramin. The inhibition constants were calculated to be 2 microM and 5 microM, respectively. In addition, stibophen turned out to be a potent inhibitor of phosvitin kinase I; the inhibition constant was determined to be 10 microM.