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

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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)

A latex phagocytosis technique was used to prepare relatively pure plasma membranes with inside-out orientation. This method was adapted through a number of modifications in order to evaluate the association of glycolytic enzymes with the cytoplasmic side of the plasma membrane of C6 glial cells. As phosphorylation is strictly coupled with transport in these cells, glycolytic enzymes, especially hexokinase, could metabolize glucose in close vicinity to its transporter. Of the enzymes tested, hexokinase is present in considerable quantities on these membranes (nearly 40% of homogenate specific activity), followed by D-glyceraldehyde-3-phosphate dehydrogenase (10%), pyruvate kinase (8%), and 3-phosphoglycerate kinase (1%). Except for hexokinase, the enzyme pattern presented here is different from that published for other membrane preparations.
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PMID:Association of glycolytic enzymes with the cytoplasmic side of the plasma membrane of glioma cells. 335 18

To determine whether respiratory muscles undergo alterations in enzyme activities of energy metabolism as a result of increased mechanical activity, adult male Wistar rats were subjected to a prolonged endurance training program. Analysis off maximal enzyme activity patterns in the diaphragm following 15 weeks of extreme training (final running duration: 210 min per day, 27 m.min-1 at 15 degrees grade, indicated significant reductions in the marker enzymes of the citric acid cycle (citrate synthase), glycolysis (pyruvate kinase, PK; lactate dehydrogenase, LDH), ketone body utilization (3-keto acid: CoA transferase) and transamination (glutamate pyruvate transaminase, GPT). No changes were found for the enzymes of glycogenolysis (phosphorylase, PHOSPH), glycolysis (glyceraldehyde phosphate dehydrogenase, GAPDH), glucose phosphorylation (hexokinase, HK) and beta-oxidation (3-hydroxyacyl: CoA dehydrogenase, HAD) following training. In contrast, in the external intercostal muscle, increases in the range of 57-77% were noted for the enzymes CS and HAD, whereas in the internal intercostal muscles no training induced alteration was evident for these enzymes. For both the intercostal muscles, a consistent trend was noted towards a reduction in all of the glycolytic enzymes investigated, however, significantly lower values were recorded for only PK and LDH in the internal intercostals. GPT was increased in the internal intercostal muscles. These findings indicate that the response pattern observed in the enzyme activities studied following training are to some degree specific to the respiratory muscle investigated.
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PMID:Differential response of enzyme activities in rat diaphragm and intercostal muscles to exercise training. 337 43

The influence of prolactin (Prl) and bromocriptine on the specific activities of neural and glial cellular enzymes involved in carbohydrate metabolism in cerebral cortex, hypothalamus, cerebellum and pons-medulla was studied. Both Prl and bromocriptine stimulated the activity of hexokinase (HK) in the neural as well as in the glial cells. While Prl increased the activity of phosphofructokinase (PFK), glyceraldehyde-3-phosphate dehydrogenase (G-3-PDH) and pyruvate kinase (PK) in the neural cells, it decreased the same in the glial cells. On the other hand, bromocriptine elevated the activity of all these enzymes in the neural cells without any effect on the glial cells. The activities of neural cellular glucose-6-phosphate dehydrogenase (G-6-PDH) and 6-phosphogluconate dehydrogenase (6-PGDH) were inhibited by Prl, whereas bromocriptine increased the same. The activities of these enzymes in the glial cells were enhanced by both Prl and bromocriptine. Thus, the present study suggests that Prl has a differential effect on the activities of enzymes involved in Embden-Meyerhoff pathway (EMP) and hexosemonophosphate shunt (HMP) in the neural and glial cells of immature male bonnet monkeys.
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PMID:Role of prolactin on neural and glial cellular enzymes involved in carbohydrate metabolism. I. Studies on immature male bonnet monkeys. 340 16

We have developed a simple and effective method to embed whole yeast cells in Lowicryl resins with excellent ultrastructural and antigenic preservation. Using affinity-purified antibodies eluted from electrophoretically separated proteins transferred to nitrocellulose, we have shown by immunoelectron microscopy that two glycolytic enzymes, glyceraldehyde-3-phosphate dehydrogenase and hexokinase, are present in the cytoplasm and the nucleus. Carboxypeptidase Y is localized in the yeast vacuole. These results agree with earlier localization studies based on subcellular fractionation.
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PMID:Immunolocalization of glyceraldehyde-3-phosphate dehydrogenase, hexokinase, and carboxypeptidase Y in yeast cells at the ultrastructural level. 354 82

In the process of defining the recruitment of fuel and pathway selection in rainbow trout fast-twitch white skeletal muscle, it was clear that the near-maximal myosin adenosinetriphosphatase activity during a 10-s sprint was supported solely by phosphocreatine hydrolysis. A conservative estimate of the ATP turnover was 188 mumol X g wet wt-1 X min-1. It was not until the rate and force of contraction decreased that the relative contribution of anaerobic glycogenolysis became increasingly important. Over a 10-min period of burst swimming at approximately 120% of maximum aerobic steady-state swimming velocity of trout determined in a Brett-type swim tunnel, fatigue was associated with the near-depletion of glycogen in white muscle. The ATP turnover supported by anaerobic glycogenolysis was 78 mumol X g wet wt-1 X min-1. The glycolytic pathway appeared functional at this time with control sites being identified at hexokinase and phosphofructokinase (PFK-1). PFK-1 did not appear to be inhibited by low muscle pH (pH 6.66). In another exercise protocol lasting 30 min, complete exhaustion was related to glycogen depletion. The sum of all glycolytic intermediates from glucose 6-phosphate to pyruvate at exhaustion decreased by a dramatic 80% compared with the 25% decrease for the 10-min fatigue swimming protocol. This large depletion of glycolytic intermediates was accompanied by an 80% fall in ATP, a 70-80% reduction in the ATP/ADP and phosphorylation potential, and a 2.5-fold increase in the NAD/NADH. Associated with these changes was a marked displacement of the phosphoglycerate kinase (PGK), and the combined glyceraldehyde-3-phosphate dehydrogenase-PGK reactions from thermodynamic equilibrium. As a general conclusion, fatigue and exhaustion should be viewed as a multicomponent biochemical process in response to low glycogen and not leveled at one particular step of the glycolytic pathway.
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PMID:Regulation of anaerobic ATP-generating pathways in trout fast-twitch skeletal muscle. 360 83

The glucose consumption rate versus ATP content in human red cells (regulatory patterns of glycolysis) and ATP concentration versus glucose uptake rate in red cell suspension (regulatory patterns of total ATPases), when the rate of glucose uptake is constant and lower than the rate of glucose consumption at physiological conditions, were measured at different pH values. The shape of both types of kinetic curves was found to be dependent on the pH of the incubation medium but the same for the red cells taken from different donors. It is supposed that at alkaline pH, glyceraldehyde-3-phosphate dehydrogenase and phosphoglycerate kinase reactions become the rate-limiting steps of glycolysis instead of hexokinase and phosphofructokinase under physiological conditions.
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PMID:[Effect of pH on the regulatory characteristics of energy metabolism in human erythrocytes]. 376 40

The glycosomes of in vitro grown procyclic trypomastigote forms of Trypanosoma brucei were purified by three different procedures and the results compared by electron microscopy, enzyme assays and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Centrifugation on a self-forming Percoll gradient followed by a sucrose gradient centrifugation resulted in the least enriched glycosomal preparation. Centrifugation on a pre-formed Nycodenz gradient gave an improved preparation but the most homogeneous preparation of intact glycosomes was obtained after centrifugation on two successive sucrose gradients. Glycosomes purified by both the Nycodenz and double sucrose gradient procedures appeared larger than in situ glycosomes presumably due to an osmotic effect resulting from disruption of the granular matrix of the organelles. Nevertheless, there appears to be no loss of cisternal contents due to the swelling of the organelles. The glycosomes of the bloodstream form trypomastigotes purified by the same procedures show, however, no sign of swelling. A comparison of glycosomes purified from procyclic trypomastigotes and bloodstream form trypomastigotes prepared by the same double sucrose procedure demonstrated that in the glycosome of procyclic trypomastigotes: activities of hexokinase, phosphoglucose isomerase, phosphofructose kinase, aldolase and phosphoglycerate kinase and diminished by 80-100%; activities of glyceraldehyde-3-phosphate dehydrogenase, triose phosphate isomerase and glycerol-3-phosphate dehydrogenase remain unchanged or are only slightly reduced; there is an appearance of four major new proteins, among which could be phosphoenol pyruvate carboxykinase and malate dehydrogenase. These observations are in basic agreement with those by Hart et al. (Mol. Biochem. Parasitol. 12, 25-35, 1984).
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PMID:An improved purification of glycosomes from the procyclic trypomastigotes of Trypanosoma brucei. 380 43

Metabolic changes have been investigated during continuous growth of yeast cells inoculated in glucose-containing medium until the cells entered the stationary phase in response to glucose exhaustion. Well in advance of glucose exhaustion, a transition phase was observed, characterized by a decrease in the growth rate and a progressive reduction of protein and RNA accumulation. Two-dimensional gel analysis of the proteins synthesized during this stage showed that the pattern of proteins remained similar to that of log-phase cells. When the cells entered the stationary phase, protein accumulation was 10% of that in log-phase cells, and incorporation of labeled RNA precursor was undetectable. Analysis of protein synthesis gave evidence that the synthesis of 95% of the proteins present in log-phase cells was arrested in stationary-phase cells. Among the 20 proteins whose synthesis continues throughout the stationary phase were identified actin, aldehyde dehydrogenase, enolase, hexokinase, glyceraldehyde-3-phosphate dehydrogenase, and five heat shock proteins. In addition, the synthesis of six new proteins was observed. The occurrence of these new proteins in stationary-phase cells is presumed to result from the release of carbon catabolite repression due to glucose exhaustion.
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PMID:Protein synthesis during transition and stationary phases under glucose limitation in Saccharomyces cerevisiae. 388 94

Glycosomes, the microbody-like organelles containing mainly glycolytic enzymes, were purified from the long slender bloodstream form of Trypanosoma brucei EATRO 110 monomorphic strain by an improved method in which the protozoa were frozen and thawed in 15% glycerol to free, from the plasma membrane, much of the variant surface glycoprotein which used to constitute the major contaminant of our purified glycosomes. The purified glycosomes have 11 major proteins, 6 of which, tentatively identified as phosphofructose kinase, hexokinase, 3-phosphoglycerate kinase, aldolase, glyceraldehyde-3-phosphate dehydrogenase, and alpha-glycerophosphate dehydrogenase, constitute 87% of the total glycosomal protein. The bifunctional cross-linking reagents dimethyl suberimidate and dimethyl-3,3'-dithiobispropionimidate can penetrate the glycosomal membrane and cause extensive cross-linking of all the major glycosomal proteins. The cross-linked complex, insoluble in 0.1% Triton X-100 plus 0.15 M NaCl, contains all the glycosomal enzyme activities with only partial inactivations. All the enzymes are probably cross-linked into one large complex since they all sediment rapidly to the bottom of a 5-20% (v/v) sucrose density gradient. This successful cross-linking with reagents of span lengths of 11-12 A suggests close proximities among the glycosomal enzymes which may explain the extraordinarily high rate of glycolysis in T. brucei. Whether such a close association represents specific spatial arrangement required for genuine substrate channeling among the enzymes will be verified by future kinetic studies of the cross-linked enzyme complex.
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PMID:Cross-linking of the enzymes in the glycosome of Trypanosoma brucei. 399 56

1. The ability of exogenously administered cyclic AMP (adenosine 3':5'-monophosphate) to exert andromimetic action on certain carbohydrate-metabolizing enzymes was investigated in the rat prostate gland and seminal vesicles. 2. Cyclic AMP, when injected concurrently with theophylline, produced marked increases in hexokinase, phosphofructokinase, glyceraldehyde phosphate dehydrogenase, pyruvate kinase, and two hexose monophosphate-shunt enzymes, as well as alpha-glycerophosphate dehydrogenase activity in accessory sexual tissues of castrated rats. The 6-N,2'-O-dibutyryl analogue of cyclic AMP caused increases of enzyme activity that were greater than those induced by the parent compound. 3. Time-course studies demonstrated that, whereas significant increases in the activities of most enzymes occurred within 4h after the injection of cyclic AMP, maximal increases were attained at 16-24h. 4. Increase in the activity of the various prostatic and vesicular enzymes was dependent on the dose of cyclic AMP; in most instances, 2.5mg of the cyclic nucleotide/rat was sufficient to elicit a statistically significant response. 5. Administration of cyclic AMP and theophylline also produced stimulation of enzyme activities in secondary sexual tissues of immature rats. 6. Cyclic AMP and theophylline did not affect significantly any of the enzymes studied in hepatic tissue. 7. Stimulation of various carbohydrate-metabolizing enzymes in the prostate gland and seminal vesicles by cyclic AMP was independent of adrenal function. 8. Concurrent treatment with actinomycin or cycloheximide prevented the cyclic AMP- and theophylline-induced increases in enzyme activities in both castrated and adrenalectomized-castrated animals. 9. Administration of a single dose of testosterone propionate (5.0mg/100g) to castrated rats caused a significant increase in cyclic AMP concentration in both accessory sexual tissues. 10. In addition, treatment with theophylline potentiated the effects of a submaximal dose of testosterone (1.0mg/100g) on all those prostatic and seminal-vesicular enzymes that are increased by exogenous cyclic AMP. 11. The evidence indicates that cyclic AMP may be involved in triggering the known metabolic actions of androgens on secondary sexual tissues of the rat.
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PMID:Metabolic control mechanisms in mammalian systems. Involvement of adenosine 3':5'-cyclic monophosphate in androgen action. 411 Apr 60


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