the results show that , under a wide variety of experimental conditions : 1 ) the stoichiometry of atp binding ranges from 0.8 to 1 mol of atp/myosin active site for myosin , heavy meromyosin , and subfragment-1 , 2 ) 80 to 100 % of this atp binding is irreversible , 3 ) 70 to 90 % of the irreversibly bound atp is hydrolyzed in the initial pi burst , 4 ) the first order rate constant for the rate-limiting step in atp hydrolysis by heavy meromyosin is equal to the steady state heavy meromyosin atpase rate only if the latter is calculated on the basis of two active sites per heavy meromyosin molecule .
C3815884
1
C0001473
atpase