Elementary steps in the acto-H-meromyosin ATPase reaction to arterial smooth muscle.
Transient and steady state kinetics were studied in the interactions of ATP with acto-H-meromyosin reconstituted from bovine arterial heavy-meromyosin (HMM) and rabbit skeletal muscle F-actin. The results showed that the rate of dissociation of the hybrid acto-HMM induced by ATP was slower than the rate of the fluorescence enhancement of HMM, and that the rate of the P1 burst of HMM was unaffected by addition of skeletal muscle F-actin. The ATPase [EC 3.6.1.3] activity of arterial HMM was activated only slightly even with addition of high concentrations of skeletal muscle F-actin. Furthermore, the rates of dissociation of the hybrid acto-HMM induced by ATP and reassociation of dissociated arterial HMM with skeletal muscle F-actin after decomposition of ATP were much lower than those of skeletal muscle acto-HMM.
D000199:Actins / Q000494:pharmacology; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002339:Carotid Arteries / Q000201:enzymology; D002417:Cattle; D004789:Enzyme Activation; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D009130:Muscle, Smooth / Q000201:enzymology*; D009132:Muscles; D015879:Myosin Subfragments / Q000302:isolation & purification / Q000378:metabolism*; D009928:Organ Specificity; D011817:Rabbits
D000199:Actins; D015879:Myosin Subfragments; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D008274:Magnesium