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

Microinjection of frog oocytes allows the modification of intracellular levels of substrates, intermediates, cofactors and enzymes. Use of labeled glucose at specific positions has led us to conclude that oocytes utilize glucose mainly for glycogen synthesis and to a lesser extent for the pentose-P pathway. Glycolysis, glycogenolysis and gluconeogenesis are not operative in these cells. The subject of compartmentation of glucose utilization has been addressed in this paper. First, we show that microinjection of glucose results in a 30-fold increase of carbon incorporation into glycogen when compared to oocytes incubated at saturating glucose concentrations. On the other hand, carbon incorporation into CO2, remains at about the same levels in both conditions Second, microinjection of NADP+ increases CO2 release and inhibits glycogen synthesis from glucose. Third, co-injection of unlabeled intermediates affects differentially glycogen synthesis and CO2 production from labeled glucose. Finally, microinjection of pure yeast hexokinase stimulates markedly 14CO2 release and inhibits glycogen synthesis. We conclude that two separate pools of glucose-6-P exists in oocytes: one pool is committed to the pathway of glycogen synthesis while a second pool serves as substrate for the operation of the pentose-P pathway.
 ...
PMID:Search for compartments of glucose metabolism in the microinjected frog oocyte. 393 91

At the second and third trimesters of pregnancy an increase in activity of hexokinase, glucose-6-phosphate-(G6PD) and 6-phosphogluconate dehydrogenases (6-PDG) occurred simultaneously with a decrease in concentrations of NADPH2 by 26%, ATP by 17% and an increase in NADP by 10-15% in the pregnant women. Total amount of nicotinamide adenine dinucleotide phosphate was unaltered and constituted 0.082-0.075 mmole/L in erythrocytes from both pregnant and nonpregnant women. Activities of hexose monophosphate and glycolytic pathways of glucose metabolism appear to increase in erythrocytes under conditions of normal pregnancy. Concentration of oxidized glutathione tended to increase in the pregnant women, suggesting a possibility of the hexose monophosphate shunt activation.
 ...
PMID:[Pentose monophoshate pathway and the glutathione system in physiological pregnancy]. 400 57

The effect of hypoparathyroidism and low blood calcium on enzyme levels in rat liver and kidney is shown. Four animal groups were used: parathyroidectomized (PTX), PTX with CaCl2 added in the drinking water, sham-operated controls and sham-operated with CaCl2 added in the drinking water. PTX significantly lowered serum parathyroid hormone (PTH) and calcium. Supplementation of CaCl2 in the drinking water increased serum Ca levels in PTX rats but not in the controls. Significant changes in several liver and kidney enzymes were seen. Most affected were the liver NADP dependent enzymes, glucose-6-phosphate dehydrogenase and malic enzyme. Similar patterns but with relatively smaller changes were seen in the liver enzymes, lactic dehydrogenase, hexokinase, and aspartate transferase. No significant differences between the groups were seen in the levels of malic dehydrogenase, isocitric dehydrogenase, fructose-6-phosphate kinase and cholinesterase. In the kidney, which was less affected than the liver, the only significant difference was seen in the level of malic enzyme. Serum total lipids in the PTX group were significantly lower. All the changes seen were partially reversed by Ca supplementation in the drinking water.
 ...
PMID:Biochemical change in the liver and kidney of rats following parathyroidectomy. 400 1

The metabolic properties of mitochondria from rat cerebral cortex and olfactory bulb were investigated. The pyruvate-supported oxygen uptake rates by olfactory bulb mitochondria were significantly lower than those by cerebrocortical mitochondria. This is consistent with the differences in pyruvate dehydrogenase complex activities between these mitochondrial preparations. Pyruvate dehydrogenase kinase, NAD-linked isocitrate dehydrogenase, and hexokinase activities in olfactory bulb mitochondria were significantly lower than those in cerebrocortical mitochondria. However, NADP-linked isocitrate dehydrogenase, and NAD-linked and NADP-linked glutamate dehydrogenase activities in olfactory bulb mitochondria were significantly higher than those in cerebrocortical mitochondria. The differences between these two mitochondrial preparations in terms of the activities of these energy-metabolizing enzymes reflect the differences detected in the homogenates of these regions.
 ...
PMID:Differences in some of the metabolic properties of mitochondria isolated from cerebral cortex and olfactory bulb of the rat. 404 57

1. Enzymic evidence supporting the operation of the Entner-Doudoroff pathway in the anaerobic conversion of glucose into ethanol and carbon dioxide by Zymomonas mobilis is presented. 2. Cell extracts catalysed the formation of equimolar amounts of pyruvate and glyceraldehyde 3-phosphate from 6-phosphogluconate. Evidence that 3-deoxy-2-oxo-6-phosphogluconate is an intermediate in this conversion was obtained. 3. Cell extracts of the organism contained the following enzymes: glucose 6-phosphate dehydrogenase (active with NAD and NADP), ethanol dehydrogenase (active with NAD), glyceraldehyde 3-phosphate dehydrogenase (active with NAD), hexokinase, gluconokinase, glucose dehydrogenase and pyruvate decarboxylase. Extracts also catalysed the overall conversion of glycerate 3-phosphate into pyruvate in the presence of ADP. 4. Gluconate dehydrogenase, fructose 1,6-diphosphate aldolase and NAD-NADP transhydrogenase were not detected. 5. It is suggested that NAD is the physiological electron carrier in the balanced oxidation-reduction involved in ethanol formation.
 ...
PMID:The route of ethanol formation in Zymomonas mobilis. 428 42

The enzyme activities involved in fructose metabolism were measured in samples of human liver. On the basis of U/g of wet-weight the following results were found: ketohexokinase, 1.23; aldolase (substrate, fructose-1-phosphate), 2.08; aldolase (substrate, fructose-1,6-diphosphate), 3.46; triokinase, 2.07; aldehyde dehydrogenase (substrate, D-glyceraldehyde), 1.04; D-glycerate kinase, 0.13; alcohol dehydrogenase (nicotinamide adenine dinucleotide [NAD]) substrate, D-glyceraldehyde), 3.1; alcohol dehydrogenase (nicotinamide adenine dinucleotide phosphate [NADP]) (substrate, D-glyceraldehyde), 3.6; and glycerol kinase, 0.62. Sorbitol dehydrogenases (25.0 U/g), hexosediphosphatase (4.06 U/g), hexokinase (0.23 U/g), and glucokinase (0.08 U/g) were also measured. Comparing these results with those of the rat liver it becomes clear that the activities of alcohol dehydrogenases (NAD and NADP) in rat liver are higher than those in human liver, and that the values of ketohexokinase, sorbitol dehydrogenases, and hexosediphosphatase in human liver are lower than those values found in rat liver. Human liver contains only traces of glycerate kinase. The rate of fructose uptake from the blood, as described by other investigators, can be based on the activity of ketohexokinase reported in the present paper. In human liver, ketohexokinase is present in a four-fold activity of glucokinase and hexokinase. This result may explain the well-known fact that fructose is metabolized faster than glucose.
 ...
PMID:Enzymes of fructose metabolism in human liver. 438 49

1. The activities of six enzymes (hexokinase, phosphoglucose isomerase, phosphofructokinase, aldolase, glucose 6-phosphate dehydrogenase and amylase) in extracts of pea cotyledons were determined. The activities during the first 10 days after germination showed individual and characteristic changes that indicate a specific control of both synthesis and destruction of enzymes. 2. Tissue contents of glucose, inorganic phosphate, glucose 6-phosphate, fructose 6-phosphate, ATP, ADP, AMP, NAD and NADP were also determined, and a correlation is reported between the substrate concentrations at day 1 and the subsequent enzymic activity. 3. The initial NAD(+)/NADH ratio value of 1 changed to about 3 by day 4; the NADP content was lower and changes in the oxidation state were less striking. The ratio of ATP to ADP and AMP remained virtually constant.
 ...
PMID:Correlated changes of some enzyme activities and cofactor and substrate contents of pea cotyledon tissue during germination. 438 39

The activity of hepatic fructokinase increased about 2-fold in desert-derived spiny mice (Acomys cahirinus) and laboratory bred albino mice and rats, maintained on a 50% sucrose diet for 3 months. The role of fructose as the specific inducer was apparent, as 25% fructose diet produced activity increases similar to those of sucrose in contrast to 25% glucose diet. The activity of hexokinase was not affected by the sucrose diet, that of glucokinase rose marginally but those of pyruvate kinase and NADP-malate dehydrogenase rose pronouncedly, especially in the spiny mice. Fructokinase activity increased significantly only after 2 weeks on the diet and continued to rise gradually. The activities of other gycolytic enzymes rose markedly already after 3 days and peaked at about 14 days. Fasting for 48 hr did not influence fructokinase activity while markedly reducing that of glucokinase, pyruvate kinase and NADP-malate dehydrogenase. Streptozotocin diabetes in rats resulted in a 40% reduction in fructokinase activity after 14 days which was restored after 6 days of insulin treatment. The activity increases of other glycolytic enzymes were more marked. However, the fructokinase induction on the sucrose diet was evident also in diabetic rats, suggesting that the insulin and substrate effects are independent. The preference of fructose over glucose phosphorylation capacity was clearly demonstrable in the non-diabetic and diabetic rats and became enhanced on sucrose feeding. The activity of triokinase also increased on the sucrose diet in the 3 rodent species, suggesting a coordinative substrate effect on the induction of these two rate-limiting fructolysis enzymes.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Response of hepatic fructokinase to long-term sucrose diets and diabetes in spiny mice, albino mice and rats. 608 70

Adriamycin is used for the treatment of leukemia and other neoplastic processes. Unfortunately the drug has a toxic effect on some tissues. Cardiotoxicity in particular limits the use of the drug. Several hypotheses have been given to explain adriamycin heart toxicity. The authors have studied the effect of the drug on the enzymes isocitrate dehydrogenase-NADP, malic enzyme, 6-P-gluconate dehydrogenase, malic dehydrogenase-NAD+, hexokinase, and phosphofructokinase. They observed that adriamycin inhibits the NADP-dependent enzymes, and that the sulfhydryl group of the enzymes may be involved in the inhibitory action of adriamycin.
 ...
PMID:[Study of the inhibition produced by adriamycin against specific enzymes in the rat heart]. 610 Apr 65

Cells of the aerotolerant anaerobe Giardia lamblia respire in the presence of oxygen. Endogenous respiration is stimulated by glucose but not by other carbohydrates and Krebs cycle intermediates. Endogenous and glucose-stimulated respiration are insensitive to cyanide, malonate, and 2,4-dinitrophenol, but are inhibited by atabrin and iodoacetamide. G. lamblia produces ethanol, acetate and CO2 both aerobically and anaerobically either from endogenous reserves or exogenous glucose. Molecular hydrogen is not produced. The following enzyme activities were detected in homogenates: hexokinase, fructose-biphosphate aldolase, pyruvate kinase, phosphoenolpyruvate carboxykinase, malate dehydrogenase, malate dehydrogenase (decarboxylating), pyruvate synthase, acetyl-CoA synthetase, alcohol dehydrogenase (NADP+), NADH dehydrogenase, NADPH dehydrogenase, NADPH oxidoreductase and superoxide dismutase. The enzymes of energy and carbohydrate metabolism are nonsedimentable (109 000 x g for 30 min). Activities of lactate dehydrogenase, hydrogenase, phosphate acetyltransferase, acetate kinase, citrate synthase, succinate dehydrogenase, fumarate hydratase and catalase were below the limits of detection. The results suggest the occurrence of glycolysis, energy production by substrate level phosphorylation and a flavin, iron-sulfur protein mediated electron transport system as well as the absence of cytochrome mediated oxidative phosphorylation and functional Krebs cycle.
 ...
PMID:Energy metabolism of the anaerobic protozoon Giardia lamblia. 610 7


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