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 novel flow-enthalpimetric analyzer is described and its use demonstrated by an analysis in which glucose is determined by its hexokinase-catalyzed phosphorylation reaction. The method depends on measurement of the temperature differential across a column packed with glass-supported immoblized enzyme. Sample volumes of 120 mul can be used to obtain a calibration curve that is linear up to 25 mmol of glucose per liter. A precision (within-day) of 5% is generally observed in the optimum concentration range where glucose is quantitatively phosphorylated. Results by the technique correlate reasonably with those by the o-toluidine and the hexokinase/glucose-6-phosphate dehydrogenase methods: Other sugars--including fructose, glucosamine, and mannose--will interfere; galactose does not. The technique is amenable to both routine and emergency analyses.
Clin Chem 1976 Sep
PMID:An immobilized-enzyme flow-enthalpimetric analyzer: application to glucose determination by direct phosphorylation catalyzed by hexokinase. 95 91

The activities of glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate: NADP oxidoreductase, G6PD), 6 phosphate glucono dehydrogenase (6 phospho-D-gluconate: NADP oxidoreductase, 6PGD) lactate dehydrogenase (D-lactate: NAD oxidoreductase, LDH), glutamate oxaloacetate transaminase (L-aspartate: 2-oxo-glutarate aminotransferase, GOT) and hexokinase (ATP: D-hexo-6-phosphotrans-ferase, Hx) were measured over 24 h in isolated lymphocytes of normal subjects and in white cells of patients with chronic lymphatic leukaemia (CLL). The activitty patterns of all enzymes in the normal lymphocytes were similar. A computed pattern of all the results exhibited a circadian rhythm of activity with the highest level at 16.00 hours. The oscillations in the activities of the same enzymes in the CLL cells differed among the patients, although all the enzymes of the same individual showed a similar diurnal rhythmic pattern. All peaks in this group appeared between 20.00 and 08.00 hours. The possible importance of these observations in setting up therapeutic schedules was raised.
Br J Haematol 1976 Sep
PMID:Blood leucocyte enzymes. III. Diurnal rhythm of activity in isolated lymphocytes of normal subjects and chronic lymphatic leukaemia patients. 98 50

A new glucose dehydrogenase preparation has been used to determine the glucose concentration in serum or plasma with the GEMSAEC(ENI) analyzer. The reaction is sufficiently linear to be suitable for a kinetic determination. A sample volume of 15 mul or less is needed, and 14 determinations can be done simultaneously within 160 s (the time needed for loading the samples and reagents into the distribution disc plus a reaction time of 70 s). The reaction is linear up to 300 mg of glucose per 100 ml, but with special computer software linearity could be extended to 1 g of glucose per 100 ml. Day-to-day and within-day precision have been tested with a number of different sera and standards. Accuracy has been checked by comparing the results with those obtained by the hexokinase and the glucose oxidase/peroxidase methods. A better agreement was found with the hexokinase method. The proposed procedure has the advantage of involving only one enzymatic step and of directly measuring reduced coenzyme formation at 340 nm.
Clin Chem 1975 Sep
PMID:Kinetic determination of glucose with the GEMSAEC (ENI) centrifugal analyzer by the glucose dehydrogenase reaction, and comparison with two commonly used procedures. 115 1

I describe optimum kinetic procedures for measuring glucose and triglycerides in plasma and serum by enzymatic techniques. Glucose was measured by the hexokinase method at a 1000-fold sample dilution. Absorbance and concentration are linearly related for concentrations up to 4 g/liter. Results are reproducible to about 25 mg/liter (standard error). Comparisons between the kinetic glucose method described here and an automated o-toluidine and a manual end-point method showed no apparent bias between the methods; correlation coefficients were 0.998 and 0.991, respectively. Triglycerides (triacylglycerols) were measured in a fully enzymatic system by measuring free glycerol after hydrolysis with lipase. Absorbance and concentration are linearly related to greater than 2.5 g/liter at a 300-fold sample dilution. Repeatability was about 30 mg/liter (standard error). Compared with a manual method, the correlation coefficient was 0.978, with a slope of 0.93.
Clin Chem 1975 Sep
PMID:Otimum kinetic enzymatic procedures for glucose and triglycerides in plasma and serum. 115 11

We evaluated a slight modification of the automated oxidase/peroxidase method for glucose determination in blood with use of 4-aminophenazone [J. Clin. Pathol. 22, 246 (1969)]. Nonsugar reducing substances did not interfere, except for ascorbic acid in very high concentrations. Lipemic sera gave slightly lower values. Values for reproducibility, specificity, and sensitivity were closer to such values for the hexokinase method than was the case for some other commonly used methods.
Clin Chem 1975 Sep
PMID:Evaluation of an automated glucose-oxidase procedure. 115 24

Properties of the cerebral glycolytic enzyme, hexokinase, were studied in biopsy samples of human temporal lobe, obtained during lobectomy for drug-resistant epilepsy and compared "blind" with contol biopsy samples of human cerebral cortex. No significant changes in the total activity or subcellular distribution of the enzyme were observed but the Km value for glucose was altered. The 17 control samples gave a normal mean value for Km (glucose) of 0.05 mM and the 14 epileptic samples gave a significantly higher mean value of 0.09 mM. The drugs used in previous treatment of the epilepsies were "scored" with respect to type and dose; analysis of these in relation to the kinetic results eliminated the possibility that the increase in Km value was an artifact due to the drugs. The observed change in enzyme kinetic properties is discussed in terms of potential interactions of small molecules with the isoenzymes of cerebral hexokinase.
Epilepsia 1975 Sep
PMID:Kinetic properties of hexokinase in resected temporal lobes of patients with drug-resistant epilepsy. 118 19

The realtionship between growth rate and the metabolic activity of certain liver enzymes was studied using two strains of White Plymouth Rock chickens which had been selected in divergent directions for eight-week body weight. The activities of hexokinase, glucokinase, phosphofructokinase, glucose-6-phosphate dehydrogenase, citrate synthase, glycogen synthetase, glutamate dehydrogenase and aspartate transaminase were measured at 4, 8 and 20 weeks of age. The mean percentage rate of growth of the birds selected for high eight-week body weight exceeded that of the birds selected for low eight-week body weight only during the early growth period. Thereafter, and until sexual maturity, the low-line birds grew at a faster rate, relative to body size. The mature body weight of the high-line birds exceeded that of the low-line birds by a factor of approximately 1.5. A close similarity was noted between the metabolic activity of certain liver enzymes and the growth rate (relative to body size) of the birds studied. At four and eight weeks of age, the faster-growing birds (whether high- or low-line) generally exhibited a greater capacity for glucose phosphorylation and glycolysis, but a poorer capacity for glycogen synthesis, than the slower-growing birds. At twenty weeks, growth rate and metabolic activity were similar in both strains.
Poult Sci 1975 Sep
PMID:Activity of certain liver enzymes in fast- and slow-growing lines of chickens. 118 17

1. In biopsy samples of the lateral part of m. quadriceps femoris of 49 obese and 14 lean persons the activities of the following enzymes were investigated: triosephosphate dehydrogenase (TPDH), glycerolphosphate: nad dehydrogenase (GPDH), lactate dehydrogenase (LDH), hexokinase (HK), malate: NAD dehydrogenase (MDH), citrate synthase (CS) and hydroxyacyl-CoA dehydrogenase (HOADH). 2. The muscles of obese had an increased activity ratio of TPDH to CS and to HK, respectively, caused in muscles of female obese subjects by an increase of TPDH activity, in those of obese men rather by a decrease of CS and HK activities. 3. Cluster analysis brough to light the existence of three major groups. Group 1 (low activity-low LDH group), consisting of muscles of female obese subjects only, exhibited low activities of all enzymes investigated, that of LDH being so low as to possibly induce a serious deficiency of anerobic metabolism under working conditions. Group 2 (medium enzyme activity group) was characterized by medium enzyme activities, similar to that of lean controls (included in this group). This consisted of subjects of both sex. Group 3 (high enzyme activity group) consisted of obese of both sex. It was distinguished by high enzyme activities, especially of LDH. It is suggested that the groups of similar enzyme activity patterns might reflect different stages, types and/or genesis of obesity.
Pflugers Arch 1975 Sep 29
PMID:Metabolic changes in the quadriceps femoris muscle of obese people. Enzyme activity patterns of energy-supplying metabolism. 123 24

A previously found proteinase possibly involved in the modification of hexokinase to eliminate the mitochondria-binding ability without appreciable change in the catalytic activity (called hexokinase-processing enzyme hereafter), was purified by sequential chromatographies from rat liver and its properties were examined. The hexokinase-processing enzyme had carbohydrate moieties as evidenced by adsorption on immobilized concanavalin A, and had a molecular weight of about 23,000 as estimated by SDS-PAGE and gel filtration chromatography. Benzyloxycarbonyl-phenylalanyl-L-arginine-4-methylcoumaryl-7-amide (Z-Phe-Arg-MCA)-hydrolyzing activity was co-purified with this processing activity throughout the purification, while the hydrolyzing activity for benzyloxycarbonyl-L-arginyl-L-arginine-4-methylcoumaryl-7-amide (Z-Arg-Arg-MCA) was not. The processing activity, as well as Z-Phe-Arg-MCA hydrolyzing activity, was highly sensitive to cysteine proteinase inhibition, for example, by leupeptin and N-[N-3-(trans-carboxirane-2-carbonyl)-L-leucyl]agmatine (E-64). Furthermore, the enzyme preparation reacted with an antibody against cathepsin L purified from rat kidney. These results indicated that cathepsin L may be involved in the above-mentioned processing of hexokinase.
J Biochem 1992 Sep
PMID:Possible involvement of cathepsin L in processing of rat liver hexokinase to eliminate mitochondria-binding ability. 142 31

Phytomonas sp. isolated from Euphorbia characias was adapted to SDM-79 medium. Cells isolated in the early stationary phase of growth were analyzed for their capacity to utilize plant carbohydrates for their energy requirements. The cellulose-degrading enzymes amylase, amylomaltase, invertase, carboxymethylcellulase, and the pectin-degrading enzymes polygalacturonase and oligo-D-galactosiduronate lyase were present in Phytomonas sp. and were all, except for amylomaltase, excreted into the external medium. Glucose, fructose and mannose served as the major energy substrates. Catabolism of carbohydrates occurred mainly via aerobic glycolysis according to the Embden-Meyerhof pathway, of which all the enzymes were detected. Likewise, the end-products of glycolysis, acetate and pyruvate, glycerol, succinate and ethanol were detected in the culture medium, as were the enzymes responsible for their production. Mitochondria were incapable of oxidizing succinate, 2-oxoglutarate, pyruvate, malate and proline, but had a high capacity to oxidize glycerol 3-phosphate. This oxidation was completely inhibited by salicylhydroxamic acid. No cytochromes could be detected either in intact mitochondria or in sub-mitochondrial particles. Mitochondrial respiration was not inhibited by antimycin, azide or cyanide. The glycolytic enzymes, from hexokinase to phosphoglycerate kinase, and the enzymes glycerol kinase, glycerol-3-phosphate dehydrogenase, phosphoenolpyruvate carboxykinase, malate dehydrogenase and adenylate kinase, were all associated with glycosomes that had a buoyant density of about 1.24 g cm-1 in sucrose. Cytochemical staining revealed the presence of catalase in these organelles. The cytosolic enzyme pyruvate kinase was activated by fructose 2,6-bisphosphate, typical of all other pyruvate kinases from Kinetoplastida. The energy metabolism of the plant parasite Phytomonas sp. isolated from E. characias resembled that of the bloodstream form of the mammalian parasite Trypanosoma brucei.
Mol Biochem Parasitol 1992 Sep
PMID:Characterization of carbohydrate metabolism and demonstration of glycosomes in a Phytomonas sp. isolated from Euphorbia characias. 143 59


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