Partial characterization of a rabbit liver Ca(2+)-calmodulin-dependent kinase with myosin light chain phosphorylating activity.
A Ca(2+)-calmodulin-dependent protein kinase that phosphorylates the regulatory light chain of hepatocyte myosin was purified from rabbit liver. The kinase catalyzed the incorporation of phosphate into the 22-k light chains of hepatocyte myosin, resulting in a 7-fold activation of the Mg(2+)-ATPase activity by F-actin. The kinase did not show any glycogen synthase kinase activity which has previously been shown to phosphorylate isolated chicken gizzard myosin light chain. ML-7, an inhibitor specific for smooth muscle myosin light chain kinase, inhibited the liver kinase with a Ki value of 13.2 microM.
Department of Biochemistry, Juntendo University School of Medicine, Tokyo, Japan.
T
T
Ueno
H
H
Takano-Ohmuro
K
K
Kohama
S
S
Watanabe
M
M
Endo
N
N
Sato
E
E
Kominami
D000199:Actins / Q000494:pharmacology; D000818:Animals; D001381:Azepines / Q000494:pharmacology; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002645:Chickens; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D038341:Glycogen Synthase Kinases; D008099:Liver / Q000201:enzymology*; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism; D009218:Myosins / Q000378:metabolism*; D009281:Naphthalenes / Q000494:pharmacology; D010766:Phosphorylation; D011494:Protein Kinases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D011817:Rabbits
D000199:Actins; D001381:Azepines; D009281:Naphthalenes; C070571:ML 7; D011494:Protein Kinases; D038341:Glycogen Synthase Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D009219:Myosin-Light-Chain Kinase; D017301:Ca(2+) Mg(2+)-ATPase; D009218:Myosins