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)

The adenylate kinase system offers a mechanism for the rapid provision of energy by catalysing the production of ATP from ADP. Fluormetric micromethods were developed for determination of the activity of this enzyme using either formation of ADP or ATP, in each case measured by coupling to suitable dehydrogenase reactions. Both procedures yielded results in good agreement, but when ADP formation was measured an interfering phosphatase splitting of ATP had to be corrected for. Therefore, ADP was preferred as the substrate and its conversion to ATP was determined in a coupled hexokinase-glucose-6-phosphate dehydrogenase reaction yielding stoichiometric amounts of NADPH which were measured by the native fluorescence of this form of the nucleotide. The sensitivity and reproducibility of our micro-method permitted assay of small samples (50-500 ng) such as a layer of cerebellar cortical nerve cells and of insulin producing cells from the islets of Langerhans. Although not reaching the high values in muscle, these cells showed significantly higher activities than parenchymatous cells from the liver and the exocrine pancreas. The sensitivity attained is more than required for assay of clinical fine needle biopsies and is quite satisfactory for detection and estimation of adenylate kinase contaminants in enzyme preparations.
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PMID:Fluorometric microassays of adenylate kinase, an enzyme important in energy metabolism. 20 11

The 200 Oe magnetic field of power frequency produces an essential effect on metabolism in the tissue of the testicles which are highly sensitive to this factor. A single effect of the field for 24 h results in an increase in the glucose-6-phosphate dehydrogenase activity. 24-28 h after the cessation of the field action it lowers considerably as well as the cytochrome oxidase and hexokinase activities in mitochondria. The lactate dehydrogenase and succinate dehydrogenase activities increased in this case. Restoration of the initial level is marked on the 7th-14th days. Under repeated actions of the stimulation phase the enzymic activities under study (except the lactate dehydrogenase one) are decreased. The mentioned indices restore the initial level on the 14th-28th days. These changes correlates with dynamics of the testosterone level in the testicles and plasm.
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PMID:[Effect of a variable magnetic field on activity of enzymes of carbohydrate metabolism and tissue respiration in testicular tissue]. 21 74

The activity of hexokinase (HK), its isoenzymes, glucose-6-phosphatase and glucose-6-phosphate dehydrogenase, and the triiodothyronine (T3) effect on this activity in the liver tissue of mice bearing transplantable hepatoma 22a were studied in different periods of the tumor growtn. It was shown that alterations in the activity of the enzymes in the liver of tumor-bearing mice occurred already in the presence of a small tumor. More profound alterations in the activity of all enzymes studied, apart from those in the enzymatic pattern of HK, could be observed starting from day 21after the tumor transplantation. In the initial stages of the hepatoma growth the activity of the test enzymes in the liver was regulated by thyroid hormone. The effect of Ta on the activity of the enzymes in the host liver was gradually lost in the course of the tumor growth.
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PMID:[Carbohydrate metabolism enzymatic activity and its alteration under the influence of thyroid hormone during tumor growth]. 22 89

The activities of the key gluconeogenic, glycolytic, and pentose-shunt enzymes in chicken kidney were determined starting from 8 days before to 58 days after hatching. The activities of pyruvate carboxylase (PC), mitochondrial and cytosolic phosphoenolypruvate carboxykinase (PEPCK), fructose-1,6-diphosphatase (FDPase) and glucose-6-phosphatase (G6Pase) were low in the embryonic tissue but increased towards the time of hatching. After hatching, the activities of PC, mitochondrial PEPCK, and G6Pase continued to increase, but those of FDPase and cytosolic PEPCK decreased. Relatively little change in these activities was observed in chickens over 24 days old. The activities of hexokinase (HK), phosphofructokinase (PFK), pyruvate kinase (PK), and lactate dehydrogenase (LDH) increased during embryonic growth. After hatching, HK activity continued to increase and then decrease, whereas PFK appeared to decrease and then increase to prehatch levels in 28-day-old birds. LDH activity continued to increase until 8 days after hatching and remained constant thereafter. No definite pattern was discernible in the case of PK. As for the pentose-shunt enzymes, there was no significant change in glucose-6-phosphate dehydrogenase activity (G6PDH), but the activity of 6-phosphogluconate dehydrogenase (6PGDH) increased until the chickens were 14 days old and then remained relatively constant.
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PMID:Development of gluconeogenic, glycolytic, and pentose-shunt enzymes in the chicken kidney. 22 78

Fetal and adult erythrocyte characteristics were studied serially in a 30-mo-old female with juvenile chronic myelocytic leukemia. On presentation the erythrocytes exhibited predominantly fetal characteristics as indicated by 69% hemoglobin F (HbF), 1.1% hemoglobin A2 (HbA2), absent I antigen, and fetal levels of the erythrocyte enzymes, carbonic anhydrase I and II, glucose-6-phosphate dehydrogenase, hexokinase, pyruvate kinase, and lactate dehydrogenase; 100% of the erythrocytes present contained HbF. However, Orskov-Jacobs-Stewart hemolysis demonstrated that at least one adult characteristic was present. Seven months later HbF was 17%; I antigen and carbonic anhydrase I had increased to adult levels. The number of cells containing HbF had decreased to 30%. Further studies indicated that at least three new populations of red cells were present after 7 mo which had not previously been detected. Two of these populations exhibited a mixture of both fetal and adult characteristics. Such findings suggested that an ongoing disturbance of regulatory mechanisms was responsible for the variable expression of fetal versus adult erythrocyte characteristics.
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PMID:Changing erythrocyte populations in juvenile chronic myelocytic leukemia: evidence for disordered regulation. 26 91

The BIOSTATOR Systems have an on-line glucose analyzer for use with whole blood. This analyzer utilizes a novel enzyme (glucose oxidase) membrane configuration and an electrochemical cell to measure the H2O2 generated. The analyzer response is fast, accurate, precise, stable, and linearly related to the blood glucose concentration over the full range of clinical interest. Extensive correlation studies have been completed to show the agreement between this analyzer and the U.S. Food and Drug Administration's recommended hexokinase-glucose-6-phosphate dehydrogenase procedure. In addition, studies on potentially interfering substance and the differences in whole blood and plasma glucose levels have been completed.
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PMID:Evaluation of the BIOSTATOR systems glucose analyzer. 29 37

The denaturation of eight purified yeast enzymes, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, 3-phosphoglycerate kinase, alcohol dehydrogenase, beta-fructosidase, hexokinase and glucose-6-phosphate isomerase, promoted under controlled conditions by the free fatty acids myristic and oleic, is selective. Glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate:NADP+ 1 oxidoreductase, EC 1.1.1.49) is extremely sensitive to destabilization and was studied in greater detail. Results show that chain length and degree of unsaturation of fatty acids are important to their destabilizing effect, and that ligands of the enzyme can afford protection. The denaturation process results in more than one altered form. These results can be viewed in the perspective of the possibility that amphipathic substances, and in particular free fatty acids, may play a role for enzyme degradation in vivo, by initiating steps of selective denaturation.
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PMID:Selective denaturation of several yeast enzymes by free fatty acids. 35 87

We evaluated the Harleco alpha-glucosidase/hexokinase/glucose-6-phosphate dehydrogenase-coupled alpha-amylase method, bu use of the GEMSAEC centrifugal analyzer. Performance evaluation included kinetic studies of substrate and maltose hydrolysis as well as effects of endogenous glucose and fructose. The reagent was found to give a linear response with alpha-amylase activity to greater than 1200 U/liter. Within-run precision resulted in coefficients of variation (CV) of 0.9 to 3.2% over the range studied. Day-to-day precision corresponded to CV's of 2.4 to 4.4% over the same range of alpha-amylase procedure was found to be good (r = 0.997) for patients' sera examined.
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PMID:Enzyme-coupled ultraviolet determination of alpha-amylase activity with the GEMSAEC centrifugal analyzer. 35 41

Biotin deficiency resulted in an increased growth rate of Aspergillus nidulans. The activities of hexokinase and aldolase were not much changed during the growth cycle, but activities of glucose-6-phosphate dehydrogenase and NADP-linked glutamate dehydrogenase increased significantly during the exponential phase. This change was remarkable during biotin deficiency. In contrast to the higher growth rate and respiration rate during biotin deficiency the activities of NAD(P)H oxidoreductases were low. An inverse relationship between the activity of tyrosinase and melanin content was observed. A role of the DOPA-DOPA-quinone system in maintaining culture growth is suggested.
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PMID:Growth, glucose metabolism and melanin formation in biotin-deficient Aspergillus nidulans. 40 7

Detailed histochemical studies have been conducted on the distribution of various enzymes, including thiamine pyrophosphatase, alpha-glucan phosphorylase, hexokinase, glucose-6-phosphate dehydrogenase, aldolase, glycerol-3-phosphate dehydrogenase; menadion oxidoreductase, lactate dehydrogenase and succinate dehydrogenase in various components of the cerebellum of healthy adult male rats of the Wistar strain. The thiamine pyrophosphatase reaction showed the morphological patterns of the GOLGI apparatus characteristic for each kind of cells. The GOLGI apparatus is a simple network in stellate cells, but it can be classified into the same 5 categories in basket cells and GOLGI type II cells. The GOLGI apparatus in the latter 2 cell types appears to undergo cyclic changes. A few GOLGI type II cells have a supranuclear form (Type II) and some cells show disintegration and "budding-off" of the GOLGI apparatus. The GOLGI apparatus in PURKINJE cells can be classified into 4 categories including a perinuclear strand form (Type III), but most of them show randomly distributed granules and vesicles. Lightly stained networks are observable in astrocytes and oligodendrocytes. They do not show polarity in astrocytes whereas they have extensions in a few oligodendrocytes. BERGMANN glia may undergo cyclic changes indicating more advance differentiation than astrocytes and oligodendrocytes. Cerebellar glomerula show lightly stained networks with many fine granules. Granule cells, stellate cells, and basket cells are all poorly equipped equally with the EMBDEN-MEYERHOF (EM) pathway and with the hexosemonophosphate (HMP) shunt. GOLGI type II cells are richly equipped almost equally with both the EM pathway and the HMP shunt. All these neurons probably derive energy mainly from glucose in the circulating blood. PURKINJE cells may belong to the category of "usual neurons", because they are moderately equipped both with the EM pathway and the HMP shunt. However, they may derive their energy from the BERGMANN glia which have intense hexokinase activity but weak succinate dehydrogenase activity. The BERGMANN glia are more richly equipped with the HMP shunt than with the EM pathway and are rich in lactate dehydrogenase suggesting an "exceptional metabolic pattern". These glia may have active synthesizing ability. Astrocytes and oligodendrocytes are equipped with all the enzymes tested, and they show a tendency to surround the glomeruli. It is suggested that the glomerula may be surrounded by the glial sheaths with strong hexokinase activity, and that they may contain alpha-glucan phosphorylase, glucose-6-phosphate dehydrogenase, and glycerol-3-phosphate dehydrogenase in addition to the succinate dehydrogenase already reported. A few PURKINJE cells showed perinuclear concentrations of the reaction product only of succinate dehydrogenase at the sites of contacts between nucleoli and nuclear membranes. It is suggested that the nucleolus may receive adenosine at the sites of contacts between nucleoli and nuclear membranes...
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PMID:Histochemical studies on the morphology of the Golgi apparatus and on the distribution of some enzymes concerned with carbodydrate metabolism in the rat cerebellum. 40 26


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