Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.1.1 (hexokinase)
 5,274 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report the synthesis of adenosine [gamma-(S)-16O,17O,18O]triphosphate, an isotopically labeled species of ATP that is chiral at the gamma-phosphoryl group, the configuration of which has been confirmed by independent stereochemical analysis. This molecule has been used as a substrate in the reactions catalyzed by glycerol kinase and by acetate kinase. The resulting samples of isotopically labeled sn-glycerol 3-phosphate and of acetyl phosphate have been used as substrates in the alkaline phosphatase mediated transfer of the chiral phosphoryl groups to (S)-propane-1,2-diol, whence the configuration at phosphorus has been determined [Abbott, S. J., Jones, S. R., Weinman, S. A., & Knowles, J. R. (1978) J. Am. Chem. Soc. 100, 2558]. It is shown that glycerol kinase and acetate kinase (and, by virtue of an earlier correlation, pyruvate kinase and hexokinase) proceed by pathways that result in inversion of the configuration at phosphorus. The sterochemical approach provides an access to the otherwise cryptic events that are involved in phosphoryl-group transfer within the ternary complexes of these kinases and their substrates.
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PMID:Stereochemical course of phosphokinases. The use of adenosine [gamma-(S)-16O,17O,18O]triphosphate and the mechanistic consequences for the reactions catalyzed by glycerol kinase, hexokinase, pyruvate kinase, and acetate kinase. 22 19

The present study was undertaken for the purpose of evaluating the solvent perturbation technique as a method to identify enzyme catalytic residues. For establishment of expected directions and sizes of pKa perturbations for different types of acids in different classes of solvents, a study of the pKa of a series of acids in mixed solvent systems was carried out. Consistent with previous findings, the presence of organic solvents (25% v/v) increased the pKa values of neutral acids while it decreased or did not change the pKa values of cationic acids. The size of the perturbation observed was dependent on the nature of the organic solvent and on the polarity of the neutral form of the acid. The solvent perturbation studies were then extended to the catalytic aspartate residue of yeast hexokinase. The pKa of this residue was determined from the MgATP V/K profile measured in the presence and absence of organic solvents (25% v/v). While dimethylformamide and methanol induced small but perhaps significant increases in the observed pKa, dimethyl sulfoxide and propylene glycol did not. The pKa values, from the MgATP V/K profiles measured in the presence of fully saturating glucose, were not significantly increased by the organic solvents. The pKi vs. pH profile for the competitive inhibitor lyxose was also measured in the presence and absence of organic solvents. While methanol (25% v/v), dimethylformamide (25% v/v), and dioxane (17.5% v/v) induced a large increase in the pKa, propylene glycol and dimethyl sulfoxide (25% v/v) did not. The results from this investigation indicate that the solvent perturbation technique should not be relied upon indiscriminately.
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PMID:Examination of the solvent perturbation technique as a method to identify enzyme catalytic groups. 635 50

This study was undertaken to assess the effect of propane-1,2-diol(PD) ingestion on carbohydrate metabolism in female rat erythrocytes. For this purpose, two different groups of adult albino female rats were treated orally with PD at two different dose levels of 73 and 294 mg 100 g-1 body wt. The blood samples drawn from the retro-orbital sinus prior to the treatment served as the controls, whereas the treated samples were collected at peak periods (1/2 and 2 h) 2 and 7 days after the treatment. A single dose of PD was found to elevate levels of blood glucose, lactate, pyruvate and the lactate/pyruvate ratio at the peak periods (P < 0.001) and after 2 days (P < 0.001) in both the groups. A significant (P < 0.05) increase in the contents of erythrocyte 2,3-diphosphoglycerate (2,3-DPG) was observed only at the peak periods. All these parameters returned to their base level after 7 days of treatment. The activities of hexokinase (HK), 2,3-diphosphoglycerate phosphatase (2,3-DPG Pase), lactate dehydrogenase (LDH), glucose-6-phosphate dehydrogenase (G-6-PD), 6-phosphogluconate dehydrogenase (6-PGD) and aldehyde reductase II (AR II) declined markedly, whereas those of pyruvate kinase (PK) and aldose reductase increased as a result of PD ingestion. The changes in the activities of 2,3-DPG Pase and LDH were persistent up to 8 days post-treatment. The [14C]glucose flux through glycolysis and the hexose monophosphate shunt pathway in erythrocytes was found to be lowered (P < 0.001) in response to PD treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of propane-1,2-diol ingestion on carbohydrate metabolism in female rat erythrocytes. 844 Aug 77