Product release is not the rate-limiting step during cytochalasin B-induced ATPase activity of monomeric actin.
Under conditions where cytochalasin B induces ATPase activity of monomeric actin (0.3 mM MgCl2, 1 mM EGTA, 30 microns cytochalasin B, 1 mM ATP) the rate constant of the exchange of actin-bound epsilon-ATP for free ATP is about 4-6 times faster than steady state ATPase activity. When a stoichiometric ATP-actin complex is extracted with PCA (single turnover experiment) the apparent rate constant of Pi generation is not faster than steady state ATPase activity. - The experiments suggest that the hydrolysis of actin-bound ATP and not the subsequent release of hydrolysis products is rate-limiting during cytochalasin-induced ATPase activity of actin.
Dancker
P
P
Institut für Zoologie, Technischen Hochschule, Bundesrepublik Deutschland.
Hess
L
L
Ritter
K
K
D000199:Actins / Q000302:isolation & purification / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000302:isolation & purification / Q000378:metabolism*; D000818:Animals; D003571:Cytochalasin B / Q000494:pharmacology*; D007700:Kinetics; D008962:Models, Theoretical; D009132:Muscles / Q000201:enzymology; D010710:Phosphates / Q000032:analysis; D011817:Rabbits
D000199:Actins; D010710:Phosphates; D003571:Cytochalasin B; D000251:Adenosine Triphosphatases