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)

A study of post-mortem changes in human central nervous tissue has shown that within 100 h of death, no significant change occurs in the amount of nerve cell DNA and nucleolar RNA nor in some membrane-associated enzymes such as succinate dehydrogenase, NADH and NADPH diaphorase, and cytochrome oxidase. Low molecular weight RNA species, probably transfer and messenger RNA are quickly lost, but there is little alteration in ribosomal RNA content. Cytoplasmic enzymes show variable changes; phosphofructokinase activity is rapidly decreased; hexokinase is unaltered but lactate dehydrogenase, pyruvate kinase and glucose-6-phosphate dehydrogenase initially show increases in activity which subsequently decline. Oxygen uptake diminishes quickly. These findings indicate that mechanical alterations in cell structure, following death, render organelles physiologically ineffective long before any significant changes in certain constituent biochemicals are detected. This report emphasizes the great importance necessary in the selection of appropriately time matched post-mortem tissues if accurate comparative studies of many of the cells constituents are to be made.
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PMID:Post-mortem changes in human central nervous tissue and the effects on quantitation of nucleic acids and enzymes. 14 55

Experimental data suggest that contrary to the findings obtained for normal and regenerating liver of mouse, the greater part of hexokinase (HK) in transplantable hepatomas is firmly bound to mitochondrial membranes. It is shown that the ratio of the bound HK activity (HKbound) to that of total HK activity (HKtotal) diminishes with a hepatoma growth. Malignization of hepatocytes also leads to a sharp decrease in the cytochrome oxidase (CO) octivity. Though the data obtained are well-correlated with the Warburg hypothesis, there is no direct correlation between the malignancy of hepatomas evaluated by their growth rates, and the biochemical parameters of the tumours studied. On the basis of fundamental principles of Warburg's, it is proposed to evaluate energy metabolism of hepatomas by the activity and subcellular distribution patterns of HK as well as be the activity of CO, according to the expression: [(HKtotal)2//HKbound-CO+HKbound-CO]. It is demonstrated that there exists a certain linear dependence between the integral characteristics of hepatoma energetics and their growth rates.
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PMID:[Biochemical characteristics determining the rates of tumour growth in the organism]. 19 Nov 4

Sex differences in development of spontaneous liver tumors were studied in mice of CBA strain. Content of mitochondrial proteins, activities of cytochrome oxidase, glucokinase, hexokinase as well as subcellular distribution of hexokinase were also studied in primary hepatomas and in normal liver tissue of the mice of CBA and C3HA strains. Liver tumors occurred in males of CBA strain 7-fold more frequently than in females. Activities of hexokinase, glucokinase, cytochrome oxidase and content of mitochondrial proteins were distinctly alterep both in primary spontaneous hepatomas and in transplantable strains. But, contrary to the transplantable tumors, in spontaneous hepatomas hexokinase, associated with mitochondria, was not found. Decrease in activities of glucokinase and cytochrome oxidase was observed at the early stages of development of CBA strain in males as compared with females of CBA and males of C3HA strains, i.e. distinct decrease in several functional patterns of liver tissue was observed. Subcutaneous administration of orthoamine azotoluene into mice of the C3HA strain caused alteration in activity of these enzymes from liver tissue, which was typical for hepatomas, already at the early steps of development.
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PMID:[Biochemical features of the liver of high and low cancer mouse strains and primary spontaneous hepatomas]. 21 May 88

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

Activities of hexokinase, glucokinase, cytochrome oxidase as well as amount of mitochondrial protein and subcellular distribution of hexokinase were studied in rat liver tissue after administration of acetyl aminofluorene and diethyl nitrosamine. Activity of the enzymes was altered in the same direction both in the primary induced hepatomas and in transplantable tumors of liver tissue. Glucokinase was not found but the fraction of hexokinase bound to mitochondrial membranes was observed in all the primary hepatomas studied; in this property the tumors resembled the embryonal liver tissue, various tissues of mature animals and transplantable hepatomas. This pattern of distribution of the enzymes reflects biochemical and functional disdifferentiation of the hepatomas. Properties of the bound hexokinase from the hepatoma were similar to those of the enzyme from embryonal liver tissue and, hence, they were distinct as compared with the enzymatic properties of hexokinase in the transplantable hepatomas.
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PMID:[Activity of the key glycolysis and respiration enzymes in the rat liver in chemical carcinogenesis]. 22

In the subcommissural organ (SCO) of the guinea pig, rat, golden hamster, and mouse the activity and distribution of enzymes related to the energy-supplying metabolism and of some marker enzymes of different cell organelles have been investigated by means of mostly modified histochemical methods. The results were compared with findings in the ciliated ependyma of the ventricular wall and with those in the ependyma of the choroid plexus of the third ventricle. In the ependymal part of the SCO only a moderate activity of hexokinase is observed in its specialized columnar cells whereas a high activity is present both in the ciliated ependyma and the choroid plexus. - The staining pattern of glucose-6-phosphatase is similar to that of hexokinase but this enzyme is found is the SCO only. - Likewise hexokinase, glycogen granules and enzymes related to glycogen metabolism (phosphoglucomutase, uridine-diphosphoglucose pyrophosphorylase, glycogen synthetase and phosphorylase) are regularly found most numerous and active in the nuclear and supra-nuclear area of the ependymal part. These enzymes are less active in both the other ependymal regions. - Uridine-diphosphoglucose dehydrogenase could not be demonstrated in the SCO. The NADP-linked enzymes of the pentose phosphate shunt, glucose-6-phosphate and 6-phosphogluconate dehydrogenase, show a moderate activity which decreases also from the nuclear towards the apical area of the ependymal cells of the SCO. Enzymes of the glycolytic pathway, such as glucosephosphate isomerase, fructose-6-phosphate kinase, fructose-I,6-diphosphate aldolase, glyceraldehyde-3-phosphate and lactate dehydrogenase, are highly active in the SCO and are located mainly in the supranuclear area, too. Fructose-1,6-diphosphatase could not be demonstrated thus indicating that in the SCO the pathway is most probably only glycolytic but not gluconeogenetic. Compared to the ependyma of the ventricular wall and of the choroid plexus, in the SCO the M type subunits of lactate dehydrogenase predominate. Glycolytic enzymes are also very active in the choroid plexus but less in the ciliated ependyma. Compared to the ciliated ependyma and especially to the ependyma of the choroid plexus, the activities of enzymes which are only present in mitochondria (NAD-linked isocitrate dehydrogenase, succinate dehydrogenase, NAD-linked malate dehydrogenase after preextraction, cytochrome oxidase, 3-hydroxybutyrate and glycerolphosphate and glutamate dehydrogenase) are relatively low. Mitochondria are accumulated near the superior pole of the nuclei as well as in the most apical part of the ependymal cells. - The staining pattern of NADP-linked isocitrate and malate dehydrogenase as well as of NADH dehydrogenase suggests that these enzymes are localized both in and out of mitochondria. The extramitochondrial activity of the first two enzymes might be localized in the cytosol. The extramitochondrial activity of NADH dehydrogenase might be localized in the endoplasmic reticulum...
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PMID:Enzymatic organization of the subcommissural organ. 123 49

The activities of enzymes related to energy metabolism in the gastrocnemius and soleus muscles in young-adult (4 months), mature (12 months), and senescent (24 months) rats were compared after continuous (72 consecutive h) exposure to normobaric hypoxia or normoxia after the vasodilator naftidrofuryl or saline solution had been given intraperitoneally for 30 consecutive days. The maximum rats (Vmax) of the following enzyme activities in the crude extract and/or the crude mitochondrial fraction of each muscle specimen were evaluated for: the anaerobic glycolytic pathway (hexokinase, phosphofructokinase, pyruvate kinase, and lactate dehydrogenase), the tricarboxylic acid cycle (citrate synthase, and malate dehydrogenase), the electron transfer chain (cytochrome oxidase), and the NAD+/NADH redox state (total NADH cytochrome c reductase). The significance of differences between the enzyme activities at different ages or under different experimental conditions in the two tissue preparations of the two muscles were determined by ANOVA. MCA and ETA2 were used to evaluate the net effects of the experimental conditions. First, aging did not seem to affect the soleus and gastrocnemius muscles in the same way. In the gastrocnemius muscle, the major changes were seen in enzymes of the glycolytic pathway, in the crude extracts. In the soleus muscle, the more striking changes in enzyme activities as a function of aging were found in the crude mitochondrial fraction. We also found that hypoxia caused more important changes in 12-month-old rats than in those of other ages (especially the enzyme activities of the gastrocnemius muscle). Naftidrofuryl modified the effects of hypoxia only sometimes and further investigations are necessary before we can draw any conclusions about the pharmacological activity of naftidrofuryl in hypoxia.
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PMID:Effects of hypoxia and pharmacological treatment on enzyme activities in skeletal muscle of rats of different ages. 164 27

Isolated vegetative tumour cells from mice bearing the Lewis lung carcinoma showed low rates of basal respiration with both low oxygen uptake rates and cytochrome-c oxidase activity. The cells were affected by a marked Crabtree effect and a high rate of lactate production in the presence of 10 mM glucose. The glycolytic capacity of the tumour was also assessed through the measurement of the maximum activities for hexokinase, phosphofructokinase, pyruvate kinase and lactate dehydrogenase. These activities were similar to the ones found in other fast-growing, undifferentiated tumours. The concentration of fructose-2,6-bisphosphate in the tumour was 2,3 nmoles/g fresh tissue wt., a value which is of the same order of magnitude as that found in other types of highly glycolytic cells. It is concluded that the Lewis lung carcinoma follows the same pattern as other undifferentiated tumours with a high capacity for both glucose and amino acid utilization.
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PMID:The impairment of respiration by glycolysis in the Lewis lung carcinoma. 215 46

The effect of Ca2+-homopantothenate (HOPA) treatment (250 mg/kg for 5 d) has been studied by evaluating the specific activity of enzymes related to: glycolytic pathway (hexokinase, phosphofructokinase, pyruvate kinase, lactate dehydrogenase), tricarboxylic acid cycle (citrate synthase, malate dehydrogenase), mitochondrial electron transfer chain (succinate dehydrogenase, cytochrome oxidase), NADH redox state (NADH cytochrome c reductase), acetylcholine metabolism (acetylcholinesterase), and glutamate metabolism (glutamate dehydrogenase). The enzymatic activity assays were performed on homogenate in toto, nonsynaptic mitochondria and synaptosomes isolated from: cerebral cortex, hippocampus, striatum, hypothalamus, medulla oblongata, and cerebellum of normoxic rats and rats submitted to intermittent normobaric hypoxia (90:10, N2:O2). In normoxic rats, HOPA was unable to induce any modification. Hypoxia per se induced a decrease in the activity of synaptosomal cytochrome oxidase in cerebral cortex, hippocampus, and cerebellum.
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PMID:Effect of Ca2+-homopantothenate and mild hypoxia on some enzyme activities evaluated in subcellular fractions from different rat brain regions. 254 16

The purposes of the present study were to characterize the histochemical and enzymatic profiles of various hindlimb skeletal muscles, as well as to determine maximal O2 consumption (VO2max) and respiratory exchange ratios (R) during steady-state exercise in the obese Zucker rat. The changes that occurred in these parameters in response to a 6-wk training program were then assessed. Obese rats were randomly assigned to a sedentary or training group. Lean littermates served as a second control. Training consisted of treadmill running at 18 m/min up an 8% grade, 1.5 h/day, 5 day/wk for 6 wk. During week 6, VO2max and R during a steady-state run (74% max) were determined. After 2 days of inactivity, hindlimb muscles were excised, stained for fiber type and capillaries, and assayed for hexokinase, citrate synthase, cytochrome oxidase, and beta-hydroxyacetyl-CoA dehydrogenase. The obese sedentary rats demonstrated greater oxidative enzyme activities per gram of muscle tissue than their lean littermates, greater R values during submaximal exercise of the same relative intensity, and greater absolute VO2max values. Training resulted in a 20-56% increase in oxidative enzymes, a 10% increase in VO2max, and an increase in capillary density in the soleus and plantaris. There was no alteration in R values during exercise at 74% VO2max or in fiber type composition in response to exercise training. Results suggest that the muscle of the obese Zucker rat manifests a greater oxidative capacity than the muscle of its lean littermates. The apparent inability of the obese rat to increase its use of fat during submaximal exercise of the same relative intensity in response to training remains to be elucidated.
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PMID:Muscle morphological and biochemical adaptations to training in obese Zucker rats. 255 20


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