title: 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.
abstract: 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.
authors: Division of Physical Biochemistry, National Institute for Medical Research, London, United Kingdom.
authors: R
authors: R
authors: Bowater
authors: R W
authors: RW
authors: Zimmerman
authors: M R
authors: MR
authors: Webb
mesh_terms: D000199:Actins / Q000494:pharmacology; D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D004789:Enzyme Activation / Q000187:drug effects; D006868:Hydrolysis; D007700:Kinetics; D009132:Muscles / Q000032:analysis*; D015879:Myosin Subfragments / Q000378:metabolism*; D009218:Myosins / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism*; D011817:Rabbits; D014867:Water / Q000378:metabolism*
chemical_list: D000199:Actins; D015879:Myosin Subfragments; D010710:Phosphates; D014867:Water; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D009218:Myosins; D010100:Oxygen