title: High affinity of various smooth muscle myosins for skeletal F-actin demonstrated by enzyme kinetics and electron microscopy.
abstract: Myosins isolated from mixed rabbit skeletal muscle and several smooth muscles differ with respect to the rate of ATP hydrolysis and the degree of inhibition of the potassium-activated ATPase activity at saturating actin concentrations. Kinetic studies indicate that smooth muscle myosins are tightly bound to skeletal F-actin in the presence of ATp. This observation led to the hypothesis that ATP is a poor dissociating agent for smooth muscle myosin and skeletal F-actin. The kinetic interpretation was verified by electron microscopic observations of myosin binding to F-actin filaments in the presence of ATP.
mesh_terms: D000199:Actins / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D002339:Carotid Arteries; D027682:Cation Transport Proteins; D002645:Chickens; D004789:Enzyme Activation; D005895:Gizzard, Avian; D007700:Kinetics; D009130:Muscle, Smooth / Q000201:enzymology*; D009132:Muscles / Q000201:enzymology*; D009218:Myosins / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D011817:Rabbits; D013270:Stomach / Q000201:enzymology; D013552:Swine
chemical_list: D000199:Actins; D027682:Cation Transport Proteins; D011189:Potassium Chloride; D000251:Adenosine Triphosphatases; C022761:potassium transporting ATPase; D009218:Myosins