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)

A simple screening procedure for the detection of adenilate kinase (AK), hexokinase (Hx) or glucose-6-phosphate dehydrogenase (G6PD) deficiencies in blood, is described. It consists of two assays : in the first, the ATP formed by blood AK is coupled to Hx and G6PD, and in the second, the glucose-6-phosphate formed by blood Hx is coupled to G6PD. The enzyme activities are visually estimated by the reduction of NADP+ (non-fluorescent) to NADH (fluorescent). The appearance of fluorescence in the first assay indicates that the three enzyme activities are present. The absence of fluorescence could be due to the deficiency of any one of the three enzymes; in this case the second assay used in combination with the Beutler's screening test for G6PD permits the detection of the specific enzymatic deficiency.
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PMID:A simple screening procedure for adenylate kinase, hexokinase and glucose-6-phosphate dehydrogenase deficiencies. 625 22

Two enzymatic assay procedures for the measurement of 2,5-anhydrohexitol fructose analogs have been devised. Both procedures are based on the measurement of ADP formed during enzymatic phosphorylation of the analogs either by hexokinase or by fructokinase. The actual measurement makes use of the coupled assay system using pyruvate kinase, PEP, lactate dehydrogenase, and NADH. Both systems can be used to measure fructose and appropriate analogs at cuvette concentrations up to 0.10 mM. The hexokinase procedures allows the measurement of fructose, 2,5-anhydromannitol, and 2,5-anhydromannose. Glucose, which also reacts, can be removed by pretreatment of the samples with glucose oxidase. The fructokinase procedure allows the measurement of fructose, 2,5-anhydromannitol, 2,5-anhydroglucitol, and 2,5-anhydrotalitol.
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PMID:Enzymatic analysis of 2,5-anhydro-D-mannitol and related compounds. 641 7

A new and simple enzymatic assay for measuring D-mannose in serum is described. Endogenous glucose is eliminated from serum by use of glucose oxidase (EC 1.1.3.4) and catalase (EC 1.11.1.6). D-Mannose concentration is calculated from the increase in NADH formation after mannosephosphate isomerase (EC 5.3.1.8) is added. This increase is a result of coupling the following series of enzymes: hexokinase (EC 2.7.1.1), glucosephosphate isomerase (EC 5.3.1.9), and glucose-6-phosphate dehydrogenase (EC 1.1.1.49, NAD+-dependent). The study included subjects who were healthy volunteers and patients with suspected or proven fungal infections.
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PMID:Enzymatic determination of D-mannose in serum. 669 39

The activity of NAD-linked alpha-glycerol-3-phosphate dehydrogenase (NAD-G3PDH; EC 1.1.1.8) was depressed by 35% when the thyroid hormone 3,3',5-triiodo-L-thyronine (20 micrograms/liter) was added to the serum-free, hormonally supplemented medium of cultured neonatal rat heart cells. The degree of depression was greater (65%) when the medium contained normal serum levels of hydrocortisone and insulin. There is a dramatic inverse dose-response relationship between triiodothyronine levels and NAD-G3PDH activity. The classic elevation by thyroid hormones of the FAD-linked alpha-glycerol-3-phosphate dehydrogenase (FAD-G3PD; EC 1.1.99.5) was observed concurrently. The medium-glucose depletion rate in triiodothyronine-free cells was depressed 32% through 11 days-in-culture, indicating reduced glycolytic activity. The activities of nine other metabolically important enzymes which were measured during this study, including hexokinase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, phosphofructokinase, pyruvate kinase, malate dehydrogenase, NAD-isocitrate dehydrogenase, NADH cytochrome c reductase, and succinic cytochrome c reductase, did not respond to varying triiodothyronine concentrations.
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PMID:Triiodothyronine depresses the NAD-linked glycerol-3-phosphate dehydrogenase activity of cultured neonatal rat heart cells. 669 42

A serum-free, hormone-supplemented medium (SFHM) for maintaining neonatal rat heart cells in culture has been developed in this laboratory (Mohamed et al., 1983). Morphological assessment of heart cells grown in SFHM show it to be similar to commonly used serum-supplemented media. To quantitatively compare cell behavior in SFHM with serum-supplemented media, the activities of ten regulatory enzymes which represent four metabolic pathways were studied in heart cells cultured in SFHM. The enzyme activities which were measured included hexokinase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, phosphofructokinase, pyruvate kinase, NAD+-linked sn-glycerol-3-phosphate dehydrogenase, malate dehydrogenase, NAD+-linked isocitrate dehydrogenase, NADH-cytochrome c reductase, and succinic cytochrome c reductase. Rat heart cells maintained in culture on SFHM are not only qualitatively and quantitatively similar to those maintained in serum-supplemented medium but also provide a more suitable model system for metabolic studies of neonatal cardiac tissue for several reasons: 1) many enzyme activities that may represent dedifferentiation are elevated by serum; 2) NAD-linked glycerol-3-phosphate dehydrogenase activity in cells maintained on SFHM is similar to the in vivo activity; 3) cells beat at or near the in vivo frequency and can be maintained 3 months on SFHM; 4) the SFHM is chemically defined and thus can be completely manipulated by the investigator. The effects of three concentrations of hydrocortisone (HC) (5,000 ng/ml, 50 micrograms/ml, 0 ng/ml) on heart cells cultured in SFHM supported our previous conclusion that function (beating) and growth (protein accumulation) are inversely related in cultured neonatal rat heart cells.
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PMID:Control of enzyme activity levels by serum and hydrocortisone in neonatal rat heart cells cultured in serum-free medium. 674 46

The sorbitol pathway in human lenses is evaluated on the enzymic level. Adult lenses, normal and nondiabetic as well as diabetic cataracts, are found to contain limited levels of aldose reductase (AR) and high levels of polyol dehydrogenase (PD) relative to the animal lens. AR is confined primarily to the lens epithelium and is two to three times higher in juvenile lenses than in the adult lens. The level of AR in the epithelium of juvenile lenses is sufficient to cause significant osmotic stress. The Km of glucose of AR is roughly 200 mM, whereas the Km for NADPH is 0.06 mM. NADP inhibits human lens AR noncompetitively and has a Ki equivalent to the Km for NADPH. PD occurs in both the lens epithelium and cortex, remains persistently high with age, and decreases with increased cortical involvement. The Km of sorbitol for PD is 1.4 mM and for NAD is 0.06 mM. NADH (Ki 0.002 mM) competitively inhibits PD in the forward direction. PD purified 100-fold from diabetic and nondiabetic cataracts and normal lenses exhibit similar kinetic constants. PD has an extremely high Vmax in the fructose-to-sorbitol direction. The Km of fructose is 40 mM and for NADH is 0.02 mM. At high enough concentration, alrestatin also inhibits PD. The added activities of AR and PD in producing sorbitol and fructose in combination with decreased hexokinase with age may account for diabetic cataract formation in human lenses exposed to a high glucose stress. Nucleotide levels are reported for senile cataractous lenses.
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PMID:The sorbitol pathway in the human lens: aldose reductase and polyol dehydrogenase. 678 33

The mannitol cycle is an important NADPH regenerating system in Alternaria alternata. The cycle is built up to the following enzymes: mannitol 1-phosphate dehydrogenase, mannitol 1-phosphatase, mannitol dehydrogenase and hexokinase. The net reaction of one cycle turn is: NADH + NADP+ + ATP leads to NAD+ + NADPH + ADP + Pi. The enzymes needed for an operating cycle were found in Aspergillus, Botrytis, Penicillium, Pyricularia, Trichothecium, Cladosporium and Thermomyces all genera belonging to Fungi Imperfecti. The only genus of this class lacking the cycle was Candida. No genera from the classes Basidiomycetes and Phycomycetes showed any mannitol 1-phosphate dehydrogenase or mannitol 1-phosphatase activities. The genera investigated, belonging to Ascomycetes, Gibberella, Ceratocystis and Neurospora all lacked mannitol 1-phosphate dehydrogenase. It was concluded that the mannitol cycle is an important and widespread pathway for NADH oxidation and NADP+ reduction in the organisms belonging to the class Fungi Imperfecti.
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PMID:The distribution of the NADPH regenerating mannitol cycle among fungal species. 678 99

In 13 rabbits the rectus femoris muscle was freely transplanted from the left to the right side using microneurovascular anastomoses. About 7 months after surgery the muscle transplants were assessed functionally by force measurements. On the average, the transplanted muscles regained 55 percent of the maximal tetanic tension of unoperated, normal rectus femoris muscles, expressed as force per gram of muscle weight even 68 percent. After functional assessment, the muscles were weighed and then used for histologic, histochemical, planimetric, and biochemical evaluation. H&E-stained cross sections showed a high content of healthy muscle fibers; only some small atrophic and single fat cells were scattered over the cross sections. Good reinnervation over the sutured muscle nerve was confirmed by the type-grouping of muscle fibers in the NADH and myofibrillar ATPase staining. There was an excellent correlation between the functional results and the histologic picture as well as the content of choline acetyltransferase (CAT). A certain parallelism was found between the function of the transplants and the content of hexokinase, but none for the other estimated muscle enzymes, such as malate dehydrogenase (MDH), creatine kinase (CK), and lactic dehydrogenase (LDH). All enzyme levels were lower than in normal muscles. The results of this experimental series underline the utility of muscle transplantation with microneurovascular anastomoses to restore lost muscle function, even in the extremities, when strong forces are needed.
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PMID:Experimental free-muscle transplantation with microneurovascular anastomoses. 683 65

We report a new statistical tool for comparing several dry-reagent strip procedures for whole blood glucose, which produce data in both digital and ordinal form, with results by the well-studied hexokinase-glucose-6-phosphate dehydrogenase procedure coupled to NAD+-NADH. Our use of "ordinal comparison unit" allows for a more equitable comparison of such data. These strip procedures produce biases of -2.21 to 1.74 ordinal comparison units over the range of glucose values corresponding to hypoglycemia and hyperglycemia, as compared with results by the hexokinase procedure, but they are essentially equivalent when compared with each other.
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PMID:Statistical comparison of blood glucose as determined by several test-strip procedures and by a hexokinase procedure. 684 48

Previously, we described a mutation glr1-1 in Saccharomyces carlsbergensis which pleiotropically relieves the synthesis of the following enzymes from glucose repression: maltase, galactokinase, alpha-galactosidase, NADH:cytochrome c reductase, and cytochrome c oxidase (C. A. Michels and A. Romanowski, J. Bacteriol, 143:674-679, 1980.) In this report, we demonstrate that glr1-1 and two other alleles, glr1-3 and glr1-16, are also insensitive to the glucose repression of invertase synthesis. Determinations of the levels of hexokinase activity and the rate of glucose transport in these mutants show that both are reduced as compared with the parent strain. Complementation tests and genetic analysis indicate that the glr1 mutations are allelic to HXK2, the structural gene for hexokinase B. The significance of this result is discussed with regard to the mechanism of glucose repression in S. carlsbergensis.
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PMID:Pleiotropic mutations regulating resistance to glucose repression in Saccharomyces carlsbergensis are allelic to the structural gene for hexokinase B. 684 88


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