Kinetics of ATP and inorganic phosphate release during hydrolysis of ATP by rabbit skeletal actomyosin subfragment 1. Oxygen exchange between water and ATP or phosphate

J Biol Chem. 1990 Jan 5;265(1):171-6.


We have used the technique of phosphate: water oxygen exchange to measure the rate of ATP and Pi release and Pi binding to myosin subfragment 1 and actomyosin subfragment 1 from rabbit skeletal muscle. The oxygen exchange distributions for ATP and Pi release fit a simple kinetic model with a single set of rate constants for each step. For actomyosin subfragment 1 (20 degrees C, pH 7.0, I = 50 mM), the rate constant governing ATP release is approximately 8 s-1, Pi release is at approximately 60 s-1 and Pi rebinds to an ADP state at greater than 120 M-1 s-1. These rate constants are similar to those that may occur for undistorted cross-bridges within glycerinated rabbit psoas fibers (Bowater, R., Webb, M. R., and Ferenczi, M. A. (1989) J. Biol. Chem. 264, 7193-7201.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Actins / pharmacology
  • Adenosine Diphosphate / metabolism
  • Adenosine Triphosphate / metabolism*
  • Animals
  • Enzyme Activation / drug effects
  • Hydrolysis
  • Kinetics
  • Muscles / analysis*
  • Myosin Subfragments / metabolism*
  • Myosins / metabolism
  • Oxygen / metabolism*
  • Phosphates / metabolism*
  • Rabbits
  • Water / metabolism*


  • Actins
  • Myosin Subfragments
  • Phosphates
  • Water
  • Adenosine Diphosphate
  • Adenosine Triphosphate
  • Myosins
  • Oxygen