EFFECT OF NOVEL SPECIFIC MYOSIN LIGHT CHAIN KINASE INHIBITORS ON CA-2+-ACTIVATED MG-2+-ATPASE OF CHICKEN GIZZARD ACTOMYOSIN

Vascular relaxing agents such as N-(6-aminohexyl)-5-chloro-l-naphthalenesulfonamide (W-7), N2-dansyl-L-arginine-4-t-butyl-piperidine amide (No. 233), prenylamine and chlorpromazine that interact with Ca2+-regulated modulator protein of cyclic nucleotide phosphodiesterase inhibited Ca2+-dependent phosphorylation of chicken gizzard myosin light chain. Inhibition by the agents of myosin light chain phosphorylation resulted in inhibition of calcium activated, magnesium dependent adenosine triphosphatase of the gizzard actomyosin. The specificity of these agents for inhibition of light chain phosphorylation was shown by negative effect of these agents on ATPase activity of gizzard actomyosin in the phosphorylated form. Results suggest that the agents provide useful tool for the study on the Ca2+-sensitive regulatory mechanism of modulator-related enzyme systems. © 1979.