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)

Lactate has been determined to be the ground glyucolysis product in the staphylococci strains under study. Acetate and CO2 are produced in small quantities. Considerable differences in storing lactate under aerobic and unaerobic conditions have not been found. Pasteur effect reaches 20.5--23.3%. The controlling glycoysis unit study has shown that it may locate on the different sections of Embden-Meyergof-Parnas pathway. The key regulation enzyme activity of hexokinase, phosphofructokinase and pyruvatekinase has been determined.
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PMID:[Activity and characteristics of the regulation of glycolytic proteins in Staphylococcus aureus]. 314 52

The glucose flow in Xanthomonas campestris was investigated with radio-labelled glucose and by enzymological studies. Only 7% of the radioactivity was incorporated into the cell material, but 41% was oxidized to carbon dioxide and 28% transformed to xanthan. Up to 16% of cell dry weight consisted of the polysaccharide glycogen. In the presence of 2.7 mM methionine, which is an inhibitor of xanthan formation, increased carbon dioxide formation (51%) occurred. This increase was in accordance with a twofold increase in the NAD-dependent isocitrate dehydrogenase activity. The other carbon dioxide liberating enzyme, 6-P-gluconate dehydrogenase, was not influenced by methionine, but its occurrence indicates the presence of an active pentose phosphate pathway in X. campestris. Among the other enzymes detected in X. campestris was glucose dehydrogenase. The presence of this enzyme together with hexokinase indicates the operation of two different glucose metabolizing steps: one oxidative, the other phosphorylative. Only the latter directly provides phosphorylated glucose as a precursor for the activated sugars required for xanthan synthesis.
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PMID:Glucose metabolism in Xanthomonas campestris and influence of methionine on the carbon flow. 314 63

This study was performed to examine the relationship between postmortem biochemical values and cause of death. The follow samples were taken from 399 corpses: cerebrospinal fluid (CSF; n = 376, suboccipital), blood (n = 158, femoral vein), and urine (n = 101, at autopsy). (See Table 1 for causes of death) All samples were stored at -80 degrees C. A further 100 samples of blood were later taken and stored at +4 degrees C before testing. Biochemical determinations made were: glucose in CSF, blood, and urine (hexokinase method); lactate (LDH/GPT) and free acetone (HS-gas chromatography) in CSF; hemoglobin A1 in blood (microcolumn technique). In 34 cases fatal diabetic coma was considered verified by morphological and chemical findings. One hundred cases of sudden cardiac death were chosen as the main control group. In 32 of the 34 cases defined above, the value of the formula of Traub (glucose + lactate in CSF) exceeded 415 mg/dl. It is not influenced significantly by hyperglycemia or hyperlactatemia due to factors other than diabetes (i.e., carbon monoxide, asphyxia). After death the value rose till the 30th hpm, then remained stable for at least 1 week. Fatal coma was defined as the ketoacidotic form if free acetone in CSF ranged above 21 mg/l. In these cases, CSF glucose and free acetone correlated positively. Hemoglobin A1 remained stable after death. Its amount was independent from postmortem blood glucose, postmortem interval and total hemoglobin. Furthermore, the manner of storage (-80 degrees or +4 degrees C) had no significant influence on its values. In 29 of 34 cases of fatal coma, Hb A1 exceeded 12.1%. Analysis of urine glucose showed elevated levels (over 500 mg/dl) in diabetic comas. On conclusion, fatal diabetic coma seems indicated as the cause of death if measured values of postmortem biochemistry exceed the following limits: CSF-Traub 415 mg/dl, free acetone (CSF) 21 mg/l; Hb A1 12.1%; urine glucose 500 mg/dl. Most important are the Traub formula and hemoglobin A1. Usually, in fatal coma both values are elevated. If both of them are normal, diabetic coma can nearly be excluded. Combined evaluation of all values is absolutely necessary. Morphology must also always be taken into account. Consequently, a diagnosis of fatal coma can be obtained by a process of elimination.
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PMID:[Biochemical measurements of glucose metabolism in relation to cause of death and postmortem effects]. 376 99

Whereas glucose is a major substrate for pulmonary lipid synthesis, fructose has also been suggested as a potential substrate. In vivo pulmonary fatty acid synthesis is depressed in hormonally deprived conditions, such as diabetes, and this can be modified by fructose feeding, but not by glucose feeding. In this study the glucose and fructose utilizations were compared in normal, diabetic and fasting states using isolated perfused rat lungs. When (U-14C)- or (5-3H)-glucose was used as substrate, glucose utilization by lung was reduced by 50% in both the fasting and diabetic animals compared to the normal controls. Using (U-14C)-glucose as substrate, the incorporation of (14C)-label in various metabolites of glucose was significantly depressed. For example, this reduction was 50% in lactate, pyruvate and CO2, 15% in ethanol-insoluble fraction, 65% in neutral lipids, 75% in phospholipids, 80% in fatty acid moiety, 40% in deacylated fraction and 10% in the polysaccharide fractions. Refeeding the fasted animals or insulin treatment to the diabetic animals restored these depressed (14C)-recoveries to the normal levels. Fructose utilization was less than 10% of glucose utilization, but remained unaffected by fasting and diabetic states. In addition, pulmonary hexokinase enzyme activity was lowered significantly in fasting and diabetic animals, whereas fructokinase enzyme activity was not altered. Despite the low rate of fructose utilization, these results suggest that fructose may serve as an alternative substrate for pulmonary phospholipid synthesis when glucose utilization is significantly depressed.
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PMID:Nutritional and hormonal control of glucose and fructose utilization by lung. 390 22

The natural product of the glucose-6-phosphate dehydrogenase reaction is 6-phosphoglucono-delta-lactone, which must be hydrolyzed to 6-phosphogluconic acid before it can be further metabolized by 6-phosphogluconate dehydrogenase. Because this lactone is very unstable, it has been uncertain whether the enzyme that hydrolyzes it, 6-phosphogluconolactonase, is required for functioning of the hexose monophosphate pathway. We have purified glucose-6-phosphate dehydrogenase, 6-phosphogluconolactonase, and 6-phosphogluconate dehydrogenase from human erythrocytes to the point where each enzyme is essentially free of each of the other activities. We constructed an artificial hexose monophosphate pathway from these enzymes, providing as substrate 14C-labeled glucose-6-phosphate either directly or by continual generation from 14C-glucose by yeast hexokinase and adenosine triphosphate. The oxidation of 6-phosphogluconic acid was estimated by measuring the CO2 formed. In the absence of a reduced nicotinamide-adenine dinucleotide phosphate (NADPH)-oxidizing system, such as oxidized glutathione (GSSG)-glutathione reductase or phenazine methosulfate, little CO2 was formed, and the presence of 6-phosphogluconolactonase did not affect the amount that was produced. When the hexose monophosphate pathway was stimulated by providing an NADPH-oxidizing system, CO2 was produced two and a half to five times as fast in the presence of 6-phosphogluconolactonase as in its absence. These studies suggest that 6-phosphogluconolactonase is required for the functioning of the hexose monophosphate pathway when the rate of oxidation of NADPH is accelerated.
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PMID:Limiting role of 6-phosphogluconolactonase in erythrocyte hexose monophosphate pathway metabolism. 393 73

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.
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PMID:Search for compartments of glucose metabolism in the microinjected frog oocyte. 393 91

Some enzyme activities and metabolic features of the black Ma melanotic, brown MI melanotic and Ab amelanotic melanomas of hamster were investigated. The activities of hexokinase and phosphofructokinase were similar in all three melanomas, the activity of NAD-dependent glycerol-3-phosphate dehydrogenase was higher in the amelanotic melanoma and that of pyruvate kinase and lactate dehydrogenase were slightly lower in MI than in the other tumors. The activities of citrate synthase, succinate dehydrogenase and malate dehydrogenase were higher in the Ma and MI melanotic melanomas than in the Ab amelanotic melanoma. The rate of labeled CO2 production from 6-14C-glucose, 1,5-14C-citric acid and U-14C-glutamine was about 2 times higher in melanotic melanomas than in amelanotic one, while no significant differences among the three melanomas were found in respect to 1-14C-glucose and U-14C-glycerol-3-phosphate. The production of 14CO2 was much higher from 1-14C-glucose than from 6-14C-glucose in all the melanomas studied. L-DOPA stimulated the production of 14CO2 from 1-14C-glucose much stronger in the Ma and MI melanomas than in the Ab melanoma. In none of the tumors the incorporation from 6-14C-glucose to CO2 was affected by L-DOPA. It is postulated that oxidation of glucose via the pentose phosphate cycle is involved in melanogenesis.
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PMID:Metabolic characterization of three hamster melanoma variants. 406 92

1. Superovulated rat ovary slices from rats treated with 20mug. of luteininzing hormone/100g. body wt. 2hr. before death and from control animals have been incubated in vitro. Output of Delta(4)-3-oxo steroids (0.2mumole/g. wet wt./hr. in control tissue) was linear for 4hr., and was increased by approx. 70% in slices from luteinizing hormone-treated rats. Rate of oxygen consumption (90.0+/-4.6mumoles/g. wet wt./hr.) was linear for 3hr. and unaltered by luteinizing hormone treatment or addition of glucose (1mg./ml.) to the medium. 2. In slices from control animals, steady-state rate of glucose uptake was 78.0+/-2.9mug. atoms of carbon/g. wet wt./hr.; steady-state rates of lactate output, pyruvate output and incorporation of [U-(14)C]-glucose carbon atoms into carbon dioxide and total lipid extract were 60.7+/-0.9, 2.4+/-0.1, 18.0+/-1.1 and 0.7+/-0.1mug. atom of carbon/g. wet wt./hr. and accounted for 104.5+/-1.9% of the glucose uptake. In slices from luteinizing hormone-treated rats, glucose uptake and outputs of lactate, pyruvate and [(14)C]carbon dioxide were increased by approx. 25%, and 108.4+/-3.2% of the glucose uptake could be accounted for. 3. The total lipid extract was separated by thin-layer chromatography and saponification. Of the (14)C incorporated into this fraction during incubation with [U-(14)C]glucose 97% was found in the fractions containing glyceride glycerol and less than 3% in the fractions containing sterols, steroids or fatty acids. Appreciable quantities of (14)C were incorporated into these lipid fractions from [1-(14)C]acetate. 4. From a consideration of the tissue glycogen content, the specific activities of [(14)C]lactate and glucose 6-phosphate (C-1) derived from [1-(14)C]-, [6-(14)C]- and [U-(14)C]-glucose, and the ratio of [(14)C]carbon dioxide yields from [1-(14)C]glucose and [6-(14)C]glucose, it was concluded that there was no appreciable glycogenolysis or flow through the pentose phosphate cycle. 5. In ovary slices from both control and luteinizing hormone-treated animals, glucose in vitro raised the incorporation rate of (14)C from [1-(14)C]acetate into sterols and steroids. Luteinizing hormone in vivo stimulated the incorporation rate in vitro but only in the presence of glucose. 6. In slices incubated in medium containing [(3)H]water, [(14)C]sorbitol and glucose (1mg./ml.), the total water space (865+/-7.1mul./g.) and the extracellular water space (581+/-22mul./g.) were unchanged by luteinizing hormone treatment in vivo but the glucose space was raised from 540+/-23.6mul./g. to 639+/-31.3mul./g. 7. Luteinizing hormone treatment was found to lower the tissue concentration of the hexose monophosphates and to increase the total activity of hexokinase, glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase and possibly of phosphofructokinase. 8. The kinetic properties of a partially purified preparation of phosphofructokinase were found to be qualitatively similar to those from other mammalian tissues. 9. The results are discussed with reference to both the role of glucose metabolism in steroidogenesis and the mechanism by which luteinizing hormone increases the rate of glucose uptake.
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PMID:Glucose metabolism in the superovulated rat ovary in vitro. Effects of luteinizing hormone and the role of glucose metabolism in steroidogenesis. 424 Jul 7

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.
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PMID:The route of ethanol formation in Zymomonas mobilis. 428 42

1. The products of the lactoperoxidase-catalysed oxidation of thiocyanate by hydrogen peroxide were sulphate, carbon dioxide and ammonia. Cyanate, sulphite and a compound showing increased extinction at 235mmu (the ;235 compound') were intermediate oxidation products. 2. Two of the intermediates acted as electron acceptors in the oxidation of NADH(2). Thus NADH(2) was oxidized by sulphite in the presence of lactoperoxidase (EC 1.11.1.7) and Mn(2+) and by the ;235 compound' in the presence of an enzyme, the NADH(2)-oxidizing enzyme, present in extracts of lactoperoxidase-resistant streptococci. Sulphur dicyanide also acted as an electron acceptor in the latter reaction. The ;235 compound' was also reduced non-enzymically by sulphite. 3. The glycolysis of lactoperoxidasesensitive streptococci suspended in glucose solution was not inhibited by sulphite, cyanate, cyanide or the ;235 compound' but was inhibited by sulphur dicyanide. The inhibition by 0.1mm-sulphur dicyanide could be reversed, as could that caused by lactoperoxidase, thiocyanate and hydrogen peroxide, by washing the cells or by the addition of a cell-free extract of a lactoperoxidase-resistant streptococcus. 4. The effects of 0.1mm-sulphur dicyanide on catabolic enzymes of resting streptococci were very similar to those of the lactoperoxidase-thiocyanate-hydrogen peroxide system. Thus hexokinase was completedly inhibited, glucose 6-phosphate dehydrogenase and aldolase were partially inhibited and phosphohexokinase was little affected in both cases.
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PMID:The inhibition of streptococci by lactoperoxidase, thiocyanate and hydrogen peroxide. The oxidation of thiocyanate and the nature of the inhibitory compound. 533 6


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