WEISER,MILTON M., HELEN QUILL, AND KURT J. ISSELBACHER. effects c~f diet on rat intestinal soluble hexokinase and fructokinase activities. Am. J. Physiol. 221(3) : 844-849. 1971 .-The effects of diet on rat intestinal hexokinase activity, hexokinase isozymes, and fructokinase activity were evaluated by separation of these enzymes with DEAEcellulose chromatography. Casein noncarbohydrate diets d...

Hexokinase isozyme I is proposed to be associated with mitochondria in vivo. Moreover, it has been suggested that this association is modulated in coordination with changes in cell metabolic state. To test these hypotheses, we analyzed the subcellular distribution of hexokinase relative to mitochondria in paraformaldehyde-fixed astrocytes using immunocytochemistry and quantitative three-dimensi...

The nonspecific hexokinases of rat intestinal epithelium were isolated by diethylaminoethyl column chromatography. The major isoenzymes of hexokinase which were found were types I and II, but, in addition, the presence of types III and IV in small amounts was suggested. The nonspecific hexokinases were clearly separated from specific fructokinase and from N-acetylglucosamine kinase, an enzyme p...

Further studies of mitochondrially bound hexokinase have been carried out in order to elucidate the mechanism first proposed to increase efficiency of oxidative phosphorylation by the acceptor effect (Bessman, S. P. (1954) in Fat Metabolism (Najjar, V., ed) pp. 133-137, Johns Hopkins Press, Baltimore). During isolation of mitochondria, Mg2+ caused increased quantities of hexokinase to be bound ...

After tissue homogenization, 43% of the total hexokinase activity found in maize radicles was recovered in the mitochondrial fraction and 35% was soluble, in the cytosol. The maize submitochondrial particles obtained after mitochondrial sonication retained a high hexokinase activity. The mitochondrial respiration (state 4 rate) was activated by glucose. This activation was blocked by carboxyatr...

1. The inhibition of hexokinase by glucose 6-phosphate has been investigated in crude homogenates of guinea-pig cerebral cortex by using a sensitive radio-chemical technique for the assay of hexokinase activity. 2. It was observed that 44% of cerebral-cortex hexokinase activity did not sediment with the microsomal or mitochondrial fractions (particulate fraction), and this is termed soluble hex...

iii CHAPTER 1: GENERAL INTRODUCTION 1 Hexokinase and its isozymes 1 Structure of Hexokinase and G6P inhibition 4 Mitochondrial Binding of hexokinase 8 Hypotheis 10 Thesis Organization 11 References 11 CHAPTER 2: SINGLE-RESIDUE DETERMINANTS IN THE BINDING OF RECOMBINANT HUMAN BRAIN HEXOKINASE TO THE MITOCHONDRION 18 Abstract 18 Introduction 19 Experimental Procedures 22 Results 25 Discussion 37 ...

Yeast hexokinase (ATP:D-hexose 6-phosphotransferase, EC 2.7.1.1), a homodimer, was rapidly and irreversibly inactivated by o-phthalaldehyde at 25 degrees C (pH 7.3). The reaction followed pseudo-first-order kinetics over a wide range of the inhibitor concentration. The second-order-rate constant for the inactivation of hexokinase was estimated to be 45 M-1.s-1. Hexokinase was protected more by ...

Phosphorylation of glucose by hexokinase is the key step in glucose and energy metabolism of the cell. In the Morris hepatoma 3924A, hexokinase II is the predominant hexokinase isoenzyme and occurs in the cytosol as well as bound to membranes. Hexokinase II was isolated by DEAE-cellulose chromatography from both the cytosolic and the mitochondria-enriched fractions and further resolved by hydro...

The highly glucolytic hepatoma cell line H-91 is characterized by a high hexokinase activity to rat liver; 50% of this activity is associated with the mitochondrial fraction [Bustamante, E., & Pederson, P.L. (1977) Proc. Natl. Acad. Sci. U.S.A. 74, 3735--3739]. Treatment of mitochondria from this cell line with adenosine 5'=triphosphate (ATP) or glucose 6-phosphate solubilizes bound hexokinase ...