Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:2.7.1.1 (hexokinase)
5,274 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The growth of Brucella abortus (US-19) in a complex tryptose-yeast extract medium containing D-glucose is inhibited by 10 mM erythritol. The enzymes of the erythritol pathway, except for D-erythrulose 1-phosphate dehydrogenase (D-glycero-2-tetrulose 1-phosphate:nicotinamide adenine dinucleotide (NAD+) 4-oxidoreductase) were detected in the soluble and membrane fractions of cell extracts. Glucose catabolism by cell extracts was inhibited by erythritol, whereas, phosphorylated intermediates of the hexose monophosphate pathway were converted to pyruvic acid with oxygen consumption. Erythritol kinase (EC 2.7.1.27; adenosine 5'-triphosphate (ATP): erythritol 1-phosphotransferase) was found to be eightfold higher in activity than the hexokinase in cell extracts. In vivo, ATP is apparently consumed with the accumulation of D-erythrulose 1-phosphate (D-glycero-2-tetrulose 1-phosphate) and no substrate level phosphorylation. ATP levels dropped 10-fold in 30 min after addition of erythritol to log phase cells in tryptose-yeast extract medium with D-glucose as the carbon source. These data suggest bacteriostasis in the presence of erythritol results from the ATP drain caused by erythritol kinase.
...
PMID:Inhibition of growth by erythritol catabolism in Brucella abortus. 17 Feb 49

Seven subjects were fed a 3,000 kcal defined formula diet daily for 19 days. Except for one 5-day period, 50% of the total caloric intake was provided as either oral or intravenous glucose. The study was divided into four periods as follows: period I lasted 5 days and provided 50% of calories as glucose; period II lasted 5 days and provided no carbohydrate (70% fat and 30% protein); period III lasted 4 days and provided 50% of calories as intravenous glucose and 50% of calories as oral fat plus protein; period IV lasted 5 days and provided 50% of calories as oral glucose. Intestinal biopsy specimens were taken on days 3 and 5 of each period, except period III when biopsies were done only on day 4. No change in intestinal morphology occurred during the study. The carbohydrate-free diet caused the alpha-glucosidase (maltase and sucrase) activities to decrease significantly from that seen with the glucose diet. Sucrase decreased from 14.4 +/- 1.0 to 7.1 +/- 0.9 mumoles/min per g tissue and maltase decreased from 56.1 +/- 3.4 to 30.0 +/- 2.1 mumoles/min per g tissue. Glycolytic enzyme activities decreased during the carbohydrate-free period (pyruvate kinase decreased from 236 +/- 12 to 78 +/- 8, fructose 1-phosphate aldolase decreased from 147 +/- 6 to 53 +/- 4, fructose-1,6-diphosphate aldolase decreased from 151 +/- 8 to 55 +/- 3, and hexokinase decreased from 21 +/- 3 to 7 +/- 1 nmoles/min per mg protein, respectively). Intravenous glucose caused no change in disaccharidase activities. The enzyme activities during periods I and IV were identical and significantly higher than during period II with the exception of fructose-1,6-diphosphatase which increased during period II as compared with periods I and IV. These findings provide an explanation for the transient period of decreased tolerance to dietary sugars when patients are weaned from total parenteral feedings to enteral feedings.
...
PMID:Comparison of the adaptive changes in disaccharidase, glycolytic enzyme and fructosediphosphatase activities after intravenous and oral glucose in normal men. 17 Aug 20

The activities (Vmax) of hexokinase, glycogen phosphorylase, glucose-6-phosphate dehydrogenase, phosphofructokinase, lactate dehydrogenase, citrate synthase, cytochrome c oxidase, and 3-OH-acyl-CoA dehydrogenase in human skeletal muscles were compared with the in vitro utilization of glucose and palmitic acid assessed under optimal conditions. Statistically significant correlations between substrate fluxes and enzyme activities were found suggesting that the substrate incorporation rate in vitro in some way reflects the capacity of metabolic pathways. The incorporation rate of leucine into muscle proteins was also statistically significantly correlated to the RNA concentration in the muscle tissue. Glycolytic and glycogenolytic enzymes correlated significantly to each other and correlations were also found between aerobic enzymes supporting the validity of constant proportions between certain key enzymes in human skeletal muscles.
...
PMID:Incorporation rate of glucose carbon, palmitate carbon and leucine carbon into metabolites in relation to enzyme activities and RNA levels in human skeletal muscles. 17 28

Hepatic carbohydrate metabolism in genetically diabetic mice (db/db) and their normal littermates has been studied. In db/db mice, body water was below normal and declined with age. The liver of db/db mice was abnormally large in relation to the metabolic mass of the body at all ages studied. In db/db mice, hepatic glycogenolysis, glycogen synthesis, glycogen synthetase, and phosphorylase were markedly increased. Gluconeogenesis from alanine or lactate in perfused livers of db/db mice was greater than normal per 100 g body water. Activities of fructose-1, 6-biophosphatase, glucose-6-phosphatase, glucokinase + hexokinase, and pyruvate kinase were elevated in livers of db/db mice. Diabetic mouse livers perfused with lactate showed a markedly reduced concentration of P-enolpyruvate and clear "forward crossover" between fructose-1, 6-P2 and fructose-6-P. In vivo glucose clearance, measured with [3-3H]glucose, in db/db mice was 170% that of normal mice. Data presented indicate that in livers of db/db mice: 1) glucose production is elevated prior to hyperglycemia, 2) glycogen turns over more rapidly, and 3) glycolytic and gluconeogenic enzymes are elevated paradoxically. These abnormalities are discussed from the viewpoint of their etiology.
...
PMID:Hepatic metabolism of genetically diabetic (db/db) mice. I. Carbohydrate metabolism. 17 48

The mechanism by which fatty acid addition leads to the inactivation of pyruvate dehydrogenase in intact rat liver mitochondria was investigated. In all cases the fatty acid octanoate was added to mitochondria oxidizing succinate. Addition of fatty acid caused an inactivation of pyruvate dehydrogenase in mitochondria incubated under State 3 conditions (glucose plus hexokinase), in uncoupled, oligomycin-treated mitochondria, and in rotenone-menadione-treated mitochondria, but not in uncoupled mitochondria or in mitochondria incubated under State 4 conditions. A number of metabolic conditions were found in which pyruvate dehydrogenase was inactivated concomitant with an elevation in the ATP/ADP ratio. This is consistent with the inverse relationship between the ATP/ADP ratio and the pyruvate dehydrogenase activity proposed by various laboratories. However, in several other metabolic conditions pyruvate dehydrogenase was inactivated while the ATP/ADP ratio either was unchanged or even decreased. This observation implies that there are likely other regulatory factors involved in the fatty acid-mediated inactivation of pyruvate dehydrogenase. Incubation conditions in State 3 were found in which the ATP/ADP and the acetyl-CoA/CoASH ratios remained constant and the pyruvate dehydrogenase activity was correlated inversely with the NADH/NAD+ ratio. Other State 3 conditions were found in which the ATP/ADP and the NADH/NAD+ ratios remained constant while the pyruvate dehydrogenase activity was correlated inversely with the acetyl-CoA/CoASH ratio. Further evidence supporting these experiments with intact mitochondria was the observation that the pyruvate dehydrogenase kinase activity of a mitochondrial extract was stimulated strongly by acetyl-CoA and was inhibited by NAD+ and CoASH. In contrast to acetyl-CoA, octanoyl-CoA inhibited the kinase activity. These results indicate that the inactivation of pyruvate dehydrogenase by fatty acid in isolated rat liver mitochondria may be mediated through effects of the NADH/NAD+ ratio and the acetyl-CoA/CoASH ratio on the interconversion of the active and inactive forms of the enzyme complex catalyzed by pyruvate dehydrogenase kinase and pyruvate dehydrogenase phosphatase.
...
PMID:Regulation of pyruvate dehydrogenase by fatty acid in isolated rat liver mitochondria. 17 49

The pathway of glucose metabolism in Pseudomonas aeruginosa was regulated by the availability of glucose and related compounds. On changing from an ammonium limitation to a glucose limitation, the organism responded by adjusting its metabolism substantially from the extracellular direct oxidative pathway to the intracellular phosphorylative route. This change was achieved by repression of the transport systems for gluconate and 2-oxogluconate and of the associated enzymes for 2-oxogluconate metabolism and gluconate kinase, while increasing the levels of glucose transport, hexokinase and glucose 6-phosphate dehydrogenase. The role of gluconate, produced by the action of glucose dehydrogenase, as a major inhibitory factor for glucose transport, and the possible significance of these regulatory mechanisms to the organism in its natural environment, are discussed.
...
PMID:The role of glucose limitation in the regulation of the transport of glucose, gluconate and 2-oxogluconate, and of glucose metabolism in Pseudomonas aeruginosa. 17 10

Some factors that influence the values of respiratory activities of liver mitochondria isolated from surgical biopsy specimens have been studied. By sedimentating of mitochondria at a lower centrifugal force (5,500 g) than usually used for rat liver mitochondria, and washing the mitochondrial pellet twice, the contamination with lysosomes and microsomes was lowered. At 37 degrees C, and in the presence of hexokinase and glucose, the oxygen uptake was greater than at 25 degrees C and in their absence. The respiratory control was good and the respiratory activities were rather stable during the first 3-4 h after isolation. The respiratory activities of mitochondria isolated from patients with duodenal or gastric ulcers, biliary diseases, and subjects with no digestive diseases (all having normal liver) were compared. Differences in oxygen uptake and acceptor control index values with some substrates were noted. The conditions for selection of controls in studies on subcellular fractions of human liver include: absence of any hepatic antecedents; no clinical evidence of liver involvement; no abnormality in routine liver function tests; a histologic aspect free of pathological conditions, and a normal aspect of the tissue during the homogenization and the fractionation procedure (absence of steatosis or fibrosis). These data provide a basis for the standardization of methods in establishing the reference values of mitochondrial activities for the modifications in a variety of diseases.
...
PMID:Factors influencing the establishment of the normal values of the respiratory activities of human liver mitochondria. 17 6

A difference in the mode of inhibition of hexokinase [EC 2.7.1.1] isoenzymes by p-chloromercuribenzenesulfonate was confirmed with respect to glucose between two Type I isoenzyme preparations purified from the kidney and spleen of rat. Essentially the same difference was observed when galactose was used as the substrate in place of glucose, as the kidney Type I isoenzyme was inhibited in a competitive manner while the spleen counterpart was inhibited in a non-competitive manner by sulfhydryl inhibitor. Both the Type I isoenzymes, however, were competitively inhibited by other mercurial sulfhydryl inhibitors, methyl and butyl mercuric chlorides. On the other hand, the Type II hexokinase isoenzymes purified from the muscle, heart, and spleen were all inhibited competitively by p-chloromercuribenzenesulfonate with respect to glucose. The mechanism of competitive inhibition of the hexokinase isoenzymes by sulfhydryl inhibitors was discussed in view of the difference in the mode of action of the mercurials with different isoenzymes.
...
PMID:Competitive inhibition of hexokinase isoenzymes by mercurials. 18 69

Adenosine 5'-hypoposphate phosphorylates glucose and fructose 6-phosphate in the presence of hexokinase and fructose 6-phosphate kinase respectively. It behaves as a competitive inhibitor versus ATP in the hexokinase reaction. Its affinity for the two enzymes is similar to that of ATP, the maximal velocities being however much lower.
...
PMID:[Action of an ATP analog, adenosine 5'-hyophosphophosphate in the reactions catalysed by hexokinase and fructose-6-phosphate kinase]. 18 8

The adaptive responses of gastrointestinal enzymes, glucose tolerance, and plasma insulin to diet, folic acid, and insulin of five obese adult-onset diabetic patients were studied before and after a 30-day fast. Their data were compared to the adaptive responses of gastrointestinal enzymes to diet, folic acid, and insulin of 15 normal male volunteer subjects, ages 18 to 24. Each group during each testing period received a carbohydrate diet (50% calories as carbohydrate consisting of 1/2 glucose and 1/2 fructose) and a noncarbohydrate diet (70% of calories as corn oil and 30% as sodium caseinate) each without and with folic acid (5 mg three times per day). The effect of insulin was studied only on the carbohydrate diet plus folic acid. Our data demonstrate that obese adult-onset diabetic patients have an impaired adaptive response of jejunal carbohydrate-metabolizing enzyme activities (hexokinase, pyruvate kinase, fructose-1-6-diphosphate aldolase, fructosediphosphatase) to dietary carbohydrate, oral folic acid, and insulin when compared to normal subjects and nondiabetic obese patients. Following a 30-day fast, the obese diabetic patients showed an improvement in glucose tolerance, hyperinsulinemia, and the adaptive response of the jejunal carbohydrate-metabolizing enzyme activities to dietary carbohydrate, folic acid, and insulin. The greatest improvement in the adaptive response of the jejunal enzyme activities occurred on the carbohydrate diet.
...
PMID:Improvement in jejunal enzyme adaptation in obese adult-onset diabetic patients following a 30-day fast. 18 94


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---