Effect of C-protein on actomyosin ATPase.
The effect of C-protein on the actin-activated ATPase of column-purified skeletal muscle myosin has been investigated at varied ionic strength. At ionic strengths below about 0.1, C-protein is a potent inhibitor. The inhibition is not reversed by increasing the actin concentration, showing that it is caused by C-protein bound to the myosin filaments. When the ionic strength is raised above about 0.12, on the other hand, the inhibition vanishes and C-protein becomes a mild activator of the actomyosin ATPase. Both effects appear rapidly upon addition of C-protein to pre-formed myosin filaments, so C-protein probably acts by binding to the surface of the filaments.
D000199:Actins / Q000494:pharmacology; D000205:Actomyosin / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D002352:Carrier Proteins; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D009124:Muscle Proteins / Q000494:pharmacology*; D009132:Muscles / Q000201:enzymology; D009218:Myosins / Q000378:metabolism; D011485:Protein Binding; D011817:Rabbits; D000099163:Myosin Binding Protein C
D000199:Actins; D000205:Actomyosin; D000251:Adenosine Triphosphatases; D002352:Carrier Proteins; D009124:Muscle Proteins; D009218:Myosins; D000099163:Myosin Binding Protein C