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)

We report a method for immobilizing glucose dehydrogenase on the inside surface of nylon tubes to produce an immobilized-enzyme nylon-tube reactor. The glucose dehydrogenase reactor is integrated into the flow system of a continuous-flow analyzer to facilitate routine analysis of serum glucose at 50 samples/h. We compared results with those by the reference hexokinase/glucose-6-phosphate dehydrogenase solution method. The coefficient of correlation was r = 0.996. A glucose dehydrogenase reactor made starting with 1 mg (250 U) of enzyme was stable during eight weeks of continuous use, that is, for nearly 3500 tests. This reduced the cost of the assay by at least 50-fold, compared with that for a commercial glucose dehydrogenase test pack method.
 ...
PMID:Routine glucose determination in serum by use of an immobilized glucose dehydrogenase nylon-tube reactor. 45 81

We have adapted for glucose determination a new approach to kinetic analyses [Anal. Chem. 50, 1611 (1978)]; it is 50-fold less dependent upon some experimental variables than is a more conventional rate method. Modification of a commercially available hexokinase/glucose-6-phosphate dehydrogenase reagent system for glucose provides that the rate of production of NADH be first-order in total glucose concentration within about 30 s after sample and reagent are mixed. In the kinetic method, absorbance vs. time data recorded after 30 s and a multiple-linear-regression program are used to compute the absorbance change that would occur if the reaction were monitored to completion. Results demonstrate a linear relationship between glucose concentration and computed absorbance change. Application of the method to 51 human sera without rigorous control of either temperature or reagent composition yielded a regression equation of y = 1.01x -0.3 when kinetic results (y) were compared with equilibrium results (x) for the same samples analyzed in a hospital laboratory.
 ...
PMID:A kinetic method for glucose that is insensitive to variations in temperature and enzyme activity. 46 84

A method is described for the measurement of enzyme activity under xeric conditions. The reaction mixtures had water contents ranging between 0.1 and 0.6g/g of reaction mixture. For glucose 6-phosphate dehydrogenase, hexokinase and fumarase, enzyme activity became detectable (about 0.05% of the fully hydrated rate) when the water content was about 0.2g/g of reaction mixture, and for phosphoglucose isomerase, around 0.15g/g of reaction mixture. With the water content raised to 0.3g/g of reaction mixture the reaction rates were only increased to 0.1-3% of the fully hydrated rate. When the combined rates for phosphoglucose isomerase and glucose 6-phosphate dehydrogenase were measured, reasonable agreement was found between the experimental data and those calculated from the individual experimentally determined rates on the assumption that diffusion was not further limiting. A method was devised for measuring the diffusion coefficients of low-molecular-weight substances in solutions having low water contents. The diffusion coefficients of riboflavin in sorbitol solution decreased by about 100-fold when the water content of the latter was reduced from 3 to 0.25g/g of sorbitol. It is concluded that to detect enzyme activity a certain minimal amount of water is required and that above this minimum the rate is still restricted by diffusion limitation. The relevance of the results to the physical state of water in reaction mixtures and to metabolism in seeds and spores in xeric conditions is discussed.
 ...
PMID:The effect of restricted hydration on the rate of reaction of glucose 6-phosphate dehydrogenase, phosphoglucose isomerase, hexokinase and fumarase. 47 53

In leukocytes of exudate from diabetic rabbits, the activities of hexokinase, phosphoglucomutase and glucose-6-phosphate dehydrogenase are increased, and a tendency of adenylate kinase activity to decline is observable. The activities of UDP-pyrophosphatase, UDP-glycogentransferase, 6-phosphogluconate dehydrogenase and glutahione reductase in the exudate erythrocytes in diabetes are not essentially altered. The decrease of the key enzymes of glycolysis and pentose phosphate cycle, providing the leukocytes with energy and metabolites, reduces the functional activity of leukocytes from exudate in diabetes.
 ...
PMID:[Enzyme profile of exudate leukocytes from diabetic rabbits]. 51 96

The activities of hexokinase, glucose-6-phosphate dehydrogenase, and glycolytic enzymes were higher in the fetal myocardium of the guinea pig than at birth and fell progressively during the 1st mo of life. The alphaHBDH/LDH ratio of H to M subunits of lactate dehydrogenase, was low in the fetus and continued to rise during the 1st mo after birth. The distinction between the left and right ventricular activities of lactate dehydrogenase, which is clear in adult guinea pigs, was absent in the fetus and appeared during postnatal development. Glycogen phosphorylase activity was low in the fetus and at birth. The activities of beta-hydroxyacylcoenzyme A dehydrogenase, succinate dehydrogenase, malate dehydrogenase, and aspartate aminotransferase were low in the fetus, but had reached, or even temporarily exceeded, normal adult levels at birth. Palmitylcarnitine transferase activity was also low in the fetal heart compared with the newborn but continued to increase substantially during the first 2 wk after birth.
 ...
PMID:Myocardial enzyme activities in guinea pigs during development. 59 69

A micromethod for the determination of glucose in 20 microliter of capillary blood using glucose dehydrogenase is described. After deproteinisation with uranyl acetate, the samples are analysed by an Autoanalyzer II method or by a manual procedure. Precision and accuracy are well correlated with the hexokinase-glucose-6-phosphate dehydrogenase method. Eleven months experience have shown the practicability and economic advantages of this method.
 ...
PMID:[Microdetermination of glucose using glucose dehydrogenase, with independent sample preparation in the routine laboratory (author's transl)]. 64 49

The determination of capillary blood glucose after deproteinization using the aca is described. The method, which uses the hexokinase/glucose-6-phosphate dehydrogenase reaction, is compared with the glucose dehydrogenase method. The comparison shows that glucose values measured in capillary blood are essentially the same in both methods. The requirements for quality control are fulfilled. The method is not influenced by hemolysis, bilirubinemia, and hypertriglyceridemia.
 ...
PMID:[The determination of capillary blood glucose using the automatic clinical analyzer (aca) Dupont (author's transl)]. 64 50

We assessed the analytical performance of the co-immobilized hexokinase (EC 2.7.1.1) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49) method for D-glucose analysis on the Technicon SMAC. The enzyme-containing coils were usable for one month, or 12 000 tests. Bilirubin, hemoglobin, lipemia, creatinine, uric acid, citric acid, and ascorbic acid did not interfere. Results with this method were compared to those by the National Glucose Reference Method. The upper limits of the total error estimate (a combination of random and systematic errors) were 76, 74, and 125 mg/liter at concentrations of 500, 1200, and 3000 mg/liter, respectively. The error estimates were less than allowable errors based on medical usefulness; thus the method was judged to perform acceptably with respect to the Reference Method. We also present performance data for the routine SMAC glucose oxidase (EC 1.1.3.4)/Peroxidase (EC 1.11.1.7) 3-methyl-2-benzothianolinone hydrazone-N,N-dimethylaniline method, the direct hexokinase method with the Du Pont aca, and the glucose oxidase oxygen-rate method with the Beckman Glucose Analyzer.
 ...
PMID:Evaluation of the co-immobilized hexokinase/glucose-6-phosphate dehydrogenase method for glucose, as adapted to the Technicon SMAC. 65 1

In this communication the results of applying various histochemical semipermeable membrane techniques to the localization of several enzymes in bovine and porcine heart are presented. The Purkinje fibers of the atrioventricular conducting system of the bovine heart differ from the myocardium proper in containing a greater activity of the glycolytic and gluconeogenetic enzymes--lactate dehydrogenase, glyceraldehyde-phosphate dehydrogenase, hexokinase, glucosephosphate isomerase and phosphoglucomutase, and less activity of the aerobic enzymes--NADH: nitroBT oxidoreductase and isocitrate dehydrogenase (NADP+). The metabolic reactions obtained with Purkinje fibers of the porcine heart are less pronounced. These histochemical findings are in accordance with the impression that Purkinje fibers, compared with the common myocardial fibers, have a higher rate of anaerobic metabolism and a lower rate of aerobic metabolism. The activity of the NADPH regenerating enzymes glucose-6-phosphate dehydrogenase and phosphogluconate dehydrogenase (decarboxylating), and the activity of acid hydrolases such as non-specific esterase and acid phosphatase is higher in the Purkinje fibers of both the bovine and porcine heart.
 ...
PMID:Enzyme histochemical studies on the Purkinje fibers of the atrioventricular system of the bovine and porcine hearts. 66 82

The Glucose-Controlled Insulin Infusion System (Biostator) is a modular, computerized, feedback control system for dynamic control of blood glucose concentrations in diabetics. This on-line glucose analyzer for use with whole blood utilizes a novel enzyme (glucose oxidase)-membrane configuration and an electrochemical cell to measure the H202 generated. The analyzer exhibits both short- and long-range stability, and instrument response and analyte concentration are linearly related over the full range of clinical interest. The response is fast, accurate, and precise, and permits determination of blood glucose within 2 min from the moment the blood leaves the patient. Correlation studies were completed to show the agreement between the Biostator Glucose Analyzer and the FDA's recommended hexokinase/glucose-6-phosphate dehydrogenase procedure on whole blood (e.g., average per cent recovered for 11 concentrations between 250 and 900 mg/liter was: hexokinase, 95.6%, Biostator Analyzer, 95.9%; bias and SDd, respectively, at low, normal, and high glucose values were: 12 and 41 mg/liter at the 500 mg/liter level; 4 and 52 mg/liter at the 1000 mg/liter level, and 4 and 128 mg/liter at the 4000 mg/liter level). No appreciable interference is observed with above-normal concentrations of bilirubin, uric acid, creatinine, sodium salicylate, or dextran. Platelet adhesion, which tends to decrease the useful life of the membrane, has been significantly decreased.
 ...
PMID:Development and evaluation of a glucose analyzer for a glucose controlled insulin infusion system ((Biostator). 67 60


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