A reinvestigation of dynein ATPase kinetics and the inhibitory action of vanadate.

The kinetic properties of sea urchin flagellar dynein ATPase have been reinvestigated using a continuous assay which regenerates ATP and contains P1,P5-di(adenosine-5')pentaphosphate, a potent adenylate kinase inhibitor. Earlier studies (Shimizu, T. (1981) Biochemistry 20, 4347-4354) revealed complex, highly cooperative kinetics with respect to MgATP2- concentration in the absence of this inhibitor. With Ap5A, the kinetics are characteristic of classical Michaelis-Menten enzymes. Isolated 21 S and 14S enzyme forms were also examined, and their kinetic parameters are presented Vanadate inhibition patterns in the presence of P1,P5-di(adenosine-5')pentaphosphate lose their nonlinear character, and we observe linear noncompetitive inhibition of the "mixed" type.