Initial rate studies were employed to investigate the kinetic mechanism of action of rat skeletal muscle type II hexokinase (EC 3.7.1.1). These investigations involved the use of substrate analogs which act as competitive inhibitors and product inhibition experiments. The findings indicate that substrates n-glucose and MgATP2add randomly to hexokmase. Both products exhibit noncompetitive inhibi...

Previous studies from this laboratory have shown that mitochondrial bound hexokinase is markedly elevated in highly glycolytic hepatoma cells (Parry, D. M., and Pedersen, P.L. (1983) J. Biol. Chem. 258, 10904-10912). A pore-forming protein, porin, within the outer membrane appears to comprise at least part of the receptor site (Nakashima, R.A., Mangan, P.S., Colombini, M., and Pedersen, P.L. (1...

The cellular distribution of hexokinase isoenzymes, N-acetylglucosamine Kinase and pyruvate kinases in rat liver was studied. Hepatocytes and non-parenchymal cells with high viability and almost no cross-contamination were obtained by perfusion in situ of the liver with collagenase, with the use of an enriched cell-culture medium in all steps of cell isolation. Separation of hexokinase isoenzym...

The rate of the ATP:glucose transphosphorylase reaction catalyzed by yeast hexokinase, isozyme PII, is inhibited by lowering the pH of the reaction below 7.0, especially at suboptimal concentrations of ATP. This effect of acidity is largely overcome by activators such as orthophosphate, citrate, malate, 3-phosphoglycerate, and riboside triphosphates. Thus, in the acid range, ATP appears to serv...

Holmes, B. F., E. J. Kurth-Kraczek, and W. W. Winder. Chronic activation of 58-AMP-activated protein kinase increases GLUT-4, hexokinase, and glycogen in muscle. J. Appl. Physiol. 87(5): 1990–1995, 1999.—This study was designed to determine whether chronic chemical activation of AMPactivated protein kinase (AMPK) would increase glucose transporter GLUT-4 and hexokinase in muscles similarly to p...

The physiological roles of polyphosphates (poly P) recently found in arthropod mitochondria remain obscure. Here, the possible involvement of poly P with reactive oxygen species generation in mitochondria of Rhipicephalus microplus embryos was investigated. Mitochondrial hexokinase and scavenger antioxidant enzymes, such as superoxide dismutase, catalase, and glutathione reductase were assayed ...

1. Extractable hexokinase activity was measured in the red and white skeletal muscles of the rabbit and in the hearts and diaphragms of four animal species differing markedly in size. Activities vary over a 40-fold range, being least in white skeletal muscle of the laboratory rabbit and greatest in mouse heart. 2. Hexokinase activities correlate approximately with capacities to undertake reacti...