Evidences for Functionally Direct Coupling between Mitochondrial Phosphocreatine Formation and Oxidative Phosphorylation

Oxidative Phosphorylation계에 의한 Phosphocreatine의 생성 기작

  • Kim, Il-Han (Department of Biochemistry, College of Natural Science and Engineering, Pai Chai University)
  • 김일한 (배재대학교 이공대학 생화학과)
  • Published : 1992.09.30

Abstract

As concentration of ADP was increased, the rate of phosphocreatine formation by respiring heart mitochondria was increased. The value of apparent Km of the phosphocreatine-forming mitochondria for ADP was estimated to be 0.0185 mM. This value was much lower than that of Km for ATP (0.31 mM) which was determined from the reaction of the soluble form of mitochondrial creatine kinase. The concentration of ATP remained constant during the respiring in the presence of ADP. The rate of accumulation of oxidative-phosphorylated ATP in the mitochondrial respiration medium was continuously monitored as a function of ADP concentration with the firefly luciferase-coupled assay. In that case, exogenous creatine did not affect the rate of accumulation of ATP, indicating that phosphocreatine-forming (i.e.,respiring) mitochondria in the presence of ADP did not use the ATP in the medium as a substrate.These results suggest that the heart mitochondrial creatine kinase bound to the inner membrane functionally tight-coupled to the oxidative phosphorylating system with respect to the respired ATP.