Kinetic enhancement of bound hexokinase activity by mitochondrial respiration

Ronald E. Gots, Fredric A Gorin, Samuel P. Bessman

Research output: Contribution to journalArticle

51 Scopus citations

Abstract

These studies were designed to examine the functional relationship between respiring rat liver mitochondria and bound hexokinase. Kinetic studies were peformed varying either exogenously supplied ATP or ATP synthesized endogenously by respiring mitochondria and varied concentrations of ADP. Michaelis-Menten constants and maximum velocities were determined at two, five, and ten minutes after initiating the reactions. The Km's and Vmax's were invariant with respect to added ATP, but the apparent Km's varied considerably when endogenous substrate was utilized. At two minutes, the Km for endogenous ATP was 25% of the Km for provided ATP, but, by ten minutes, it had reached 70%. The Vmax's varied far less markedly. This is a clear demonstration of preferential utilization of mitochondrial ATP by bound hexokinase.

Original languageEnglish (US)
Pages (from-to)1249-1255
Number of pages7
JournalBiochemical and Biophysical Research Communications
Volume49
Issue number5
DOIs
StatePublished - Dec 4 1972
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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