title: A dynein ATPase inhibitor isolated from a commercial ATP preparation.
abstract: Preparations of ATP from equine muscle contained an inhibitor of dynein Mg2+-activated ATPase. The inhibitory material was separated from the ATP by molecular sieve filtration. The several molecular species of dynein extracted from three different axonemal sources were all inhibited; myosin ATPase was not. With increasing amounts of inhibitor the inhibition did not go to completion but reached a plateau when the rate had been reduced to 1/5 the uninhibited rate. A plot of 1/[S] against 1/v at several inhibitor concentrations yielded parallel lines. There was little inhibition of dynein ATPase when Mg2+ was replaced by Ca2+. The inhibitor appeared slightly smaller in molecular size than ATP, had anionic character, and was not adsorbed to charcoal.
mesh_terms: D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors*; D000255:Adenosine Triphosphate / Q000302:isolation & purification*; D000818:Animals; D002413:Cations, Divalent; D004398:Dyneins / Q000037:antagonists & inhibitors*; D004789:Enzyme Activation; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D009132:Muscles; D013769:Tetrahymena pyriformis / Q000201:enzymology
chemical_list: D002413:Cations, Divalent; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D004398:Dyneins; D008274:Magnesium