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)

Most of the enzymes involved in glycolysis are readily reversible and are also active in gluconeogenesis. However, three reaction steps are irreversible, i.e., those catalyzed by hexokinase, phosphofructokinase, and pyruvate kinase; for in each of these reactions there occurs a large negative free-energy change, and these are reactions thus bypassed by alternate enzyme-catalyzed reactions. Pyruvate kinase (EC 2.7.1.40, PK) plays an important role in controlling glycolysis and gluconeogenesis. To clarify the characteristics of glycolysis in dental pulp, we examined the enzymatic properties of pyruvate kinase from pig dental pulp and compared them with those of the enzyme from pig brain. 1) Pyruvate kinase from dental pulp and brain were purified by use of ammonium sulphate fractionation, phosphocellulose colum chromatography, and isoelectric focusing. The prepared enzymes showed a single protein band on SDS polyacrylamide gel electrophoresis. 2) The subunit molecular weight of dental pulp and brain enzymes was determined to be 63,000 and 59,000, respectively. 3) Substrate inhibition of dental pulp and brain enzymes by phosphoenolpyruvate was not observed, and the relationship between reaction velocity and substrate concentration at pH 7.2 was explained by the Michaelis-Menten equation. Fructose-1,6-diphosphate had no observable effect on either enzyme. 4) Effect of amino acids on dental pulp and brain enzyme activity were examined, and no significant relationship was observed between the side chain structure of amino acids and their potency in inhibiting dental pulp and brain enzyme activity. Glutamic and aspartic acids markedly inhibited dental pulp and brain enzymes at pH 7.2. 5) Oxalate showed inhibitory activity against dental pulp and brain enzymes, and the Ki value was determined to be 50 microM and 80 microM, respectively. The inhibition of dental pulp and brain enzyme activity by oxalate was competitive with respect to phosphoenolpyruvate. 6) Both dental pulp and brain enzymes were clearly inhibited by malate at concentrations higher than 1.0 mM: 50% and 100% inhibition occurred at 2.2-2.3 mM and 3.0 mM malate, respectively.
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PMID:[Studies on pyruvate kinase from pig dental pulp and brain]. 198 6

For the first time, alterations in the oxidative metabolism of Achatina fulica experimentally infected with different parasite loads of Angiostrongylus cantonensis were determined. For this, the hemolymph activities of lactate dehydrogenase (LDH) and hexokinase and the glucose concentrations in the hemolymph, as well as the polysaccharide reserves in the digestive gland and cephalopedal mass, were assessed. Additionally, the contents of some carboxylic acids in the hemolymph of infected and uninfected snails were determined by high-performance liquid chromatography (HPLC), permitting a better understanding of the alterations related to the host's oxidative metabolism. As the main results, activation of oxidative pathways, such as the glycolytic pathway, was demonstrated in response to the increase in the activity of hexokinase. This tendency was confirmed by the decrease in the contents of glucose in the hemolymph of parasitized snails, indicating that the infection by A. cantonensis alters the host's metabolism, and that these changes are strongly influenced by the parasite load. This metabolic scenario was accompanied by activation of the anaerobic fermentative metabolism, indicated not only by an increase in the activity of (LDH), but also by a reduction of the content of pyruvic acid and accumulation of lactic acid in the hemolymph of parasitized snails. In this circumstance, maintenance of the host's redox balance occurs through activation of the fermentative pathways, and LDH plays a central role in this process. Together, the results indicate that A. cantonensis infection induces activation of the anaerobic metabolism of A. fulica, characterized not only by the accumulation of lactic acid, but also by a reduction in the pyruvic acid and oxalic acid contents in the hemolymph of the infected snails.
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PMID:Unveiling the oxidative metabolism of Achatina fulica (Mollusca: Gastropoda) experimentally infected to Angiostrongylus cantonensis (Nematoda: Metastrongylidae). 2968 Sep 39