title: Transient-phase studies on the arginine kinase reaction.
abstract: 1. The initial formation of arginine phosphate by arginine kinase was studied in the time range 2.8--50 ms by the quenched-flow method. 2. A transient burst phase of product formation was obtained, the amplitude of which was temperature-dependent. At 35 degrees C it was 0.64 mol arginine phosphate/mol arginine kinase and at 12 degrees C, 0.25 mol/mol. 3. These results show that for the reaction pathway of arginine kinase the rate-limiting step follows the formation of arginine phosphate on the enzyme. This is in contrast to the creatine kinase reaction where no transient phase was observed [Engelborghs, Y., Marsh, A. & Gutfreund, H. (1975) Biochem. J. 151, 47--50]. 4. The rate-limiting step on the arginine kinase reaction pathway is only slightly affected by temperature: the change in Kcat with temperature is due to a change of an equilibrium constant pertaining to at least two previous steps.
mesh_terms: D000818:Animals; D001122:Arginine Kinase / Q000378:metabolism*; D003402:Creatine Kinase / Q000378:metabolism; D007700:Kinetics; D008433:Mathematics; D009132:Muscles / Q000201:enzymology; D008121:Nephropidae; D010770:Phosphotransferases / Q000378:metabolism*
chemical_list: D010770:Phosphotransferases; D003402:Creatine Kinase; D001122:Arginine Kinase