Phosphorylation of smooth muscle myosin light chain kinase by the catalytic subunit of adenosine 3': 5'-monophosphate-dependent protein kinase

R S Adelstein, M A Conti, D R Hathaway, C B Klee
1978 Journal of Biological Chemistry  
Turkey gizzard smooth muscle light chain kinase was purified by affinity chromatography on calcium dependent regulator weight of 125,000 +/- 5,000 in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. When myosin light chain kinase is incubated with the catalytic subunit of cyclic AMP-dependent protein kinase, 1 mol of phosphate is incorporated per mol of myosin kinase. Brief tryptic digestion of the 32P-labeled myosin kinase liberates a single radioactive peptide with a molecular
more » ... of approximately 22,000. Phosphorylation of myosin kinase results in a 2-fold decrease in the rate at which the enzyme phosphorylates the 20,000-dalton light chain of smooth muscle myosin. These results suggest that cyclic AMP has a direct effect on actin-myosin interaction in smooth muscle.
pmid:213432 fatcat:f536z6jwava3xg3su5n5j4macm