title: Nature of the calcium regulatory system of bovine arterial actomyosin.
abstract: A calcium-sensitive actomyosin was prepared from bovine aortic muscularis. The results of applying filament displacement tests indicate that bovine arterial actomyosin possesses predominantly a calcium regulatory system associated with the myosin filament, but also may possess a calcium regulatory system associated with the filament. Calcium binding to highly purified myosin preparations could not account for the calcium binding to calcium-sensitive actomyosin. A calcium-insensitive actomyosin preparation, prepared by omitting dithiothreitol from the isolation procedure, showed a definite loss of tropomyosin but no change in calcium binding relative to the calcium-sensitive actomyosin.
mesh_terms: D000199:Actins / Q000378:metabolism; D000205:Actomyosin / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D001013:Aorta, Thoracic / Q000378:metabolism; D001158:Arteries / Q000378:metabolism*; D001667:Binding, Competitive; D002118:Calcium / Q000378:metabolism* / Q000502:physiology; D002417:Cattle; D003599:Cytoskeleton / Q000378:metabolism; D009130:Muscle, Smooth / Q000378:metabolism*; D009218:Myosins / Q000378:metabolism; D011485:Protein Binding
chemical_list: D000199:Actins; D000205:Actomyosin; D000251:Adenosine Triphosphatases; D009218:Myosins; D002118:Calcium