The function of the N-terminal amino acids of Saccharomyces cerevisiae hexokinase II was studied in vivo using strains producing a form of hexokinase II lacking its first 15 amino acids (short form). This short form of hexokinase II was produced from a fusion between the promoter region of the PGK1 gene and the HXK2 coding sequence except the first 15 codons. As expected, the in vitro analysis ...

Recent findings have suggested an important role for variation in levels of 2,3-diphosphoglycerate and ATP in the regulation of oxygen transport by the human erythrocyte, and in making homeostatic adjustments to hypoxia. For this reason, the erythrocytic glycolytic mechanisms which control or bring about changes in levels of 2,3-diphosphoglycerate and ATP are of vital importance in understandin...

A congenic series of Saccharomyces cerevisiae strains has been constructed which carry, in all combinations, null mutations in the three genes for glucose phosphorylation: HXK1, HXK2 and GLK1, coding hexokinase 1 (also called PI or A), hexokinase 2 (PII or B), and glucokinase, respectively: i.e., eight strains, all of which grow on glucose except for the triple mutant. All or several of the str...

The outer mitochondrial membrane pore (VDAC) changes its structure either voltage-dependently in artificial membranes or physiologically by interaction with the adenine nucleotide translocase (ANT) in the c-conformation. This interaction creates contact sites and leads in addition to a specific organisation of cytochrome c in the VDAC-ANT complexes. The VDAC structure that is specific for conta...

The release of glucokinase (hexokinase IV) from digitonin-permeabilized hepatocytes from rat, guinea pig or mouse liver is inhibited by physiological concentrations of Mg2+ (> 0.25 mM). Preincubation of hepatocytes with fructose increases glucokinase release during permeabilization in the presence of Mg2+ but decreases glucokinase release in the absence of Mg2+, suggesting that fructose causes ...

Radiolabeled analogues of 2-deoxyglucose are widely used to trace glucose metabolism in cell cultures, whole organs, and intact animals, although kinetic differences in transport and phosphorylation between these compounds and glucose exist. The present studies were undertaken to determine the effects of insulin stimulation on the phosphorylation of 2-deoxyglucose compared to glucose in the int...

from Suspension-Cultured Catharanthus roseus Cells* Yüko Yamashita and Hiroshi Ashihara Department of Biology, Faculty of Science, Ochanomizu University, 2-1-1, Otsuka, Bunkyo-ku, Tokyo, 112, Japan Z. Naturforsch. 43c, 827-834 (1988); received June 28, 1988 Catharanthus roseus, Suspension Culture, Fructokinase, Glycolysis, Hexokinase Two different hexose-phosphorylating enzymes, hexokinase and ...

Radiolabeled analogues of 2-deoxyglucose are widely used to trace glucose metabolism in cell cultures, whole organs, and intact animals, although kinetic differences in transport and phosphorylation between these compounds and glucose exist. The present studies were undertaken to determine the effects of insulin stimulation on the phosphorylation of 2-deoxyglucose compared to glucose in the int...

1. The hexokinase activity of homogenates of eggs and embryos of the sea urchin Arbacia punctulata has been measured. Expressed as micrograms glucose consumed at 20 degrees C., per hour per milligram of protein the following values were obtained: unfertilized eggs, 67; fertilized eggs, 72; 24 hour plutei, 94; 48 hour plutei, 226. The concentration of the enzyme in the eggs is small and may be c...

The A isozyme of yeast hexokinase (ATP:D-hexose 6-phosphotransferase, EC 2.7.1.1) crystallized as a complex with glucose has a conformation that is dramatically different from the conformation of the B isozyme crystallized in the absence of glucose. Comparison of the high-resolution structures shows that one lobe of the molecule is rotated by 12 degrees relative to the other lobe, resulting in ...