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)

In 28 dogs the distal articular cartilage of the femur was removed and the regenerating articular surface on the 70th postoperative day was studied histochemically for hexokinase, glucose-6-phosphatase, phosphohexose-isomerase, fructose-1, 6-diphosphatase, aldolase, glyceraldehyde-3-phosphate dehydrogenase, lactate dehydrogenase, lactate dehydrogenase isoenzymes, phosphoglucomutase, phosphorylase, glycogen synthetase, UDP--glucose dehydrogenase, and UDP-glucuronic acid-4-epimerase. The articular surface consisted of fibrous tissue and of cartilage islets. The latter contained cells differentiating into cartilage and young chondrocytes. The glycolytic enzymes reacted positively in the regenerative articular surface. Enzyme activities were higher in the cells (particularly the chondroblasts and young chondrocytes) of the cartilage islets than in the connective tissue. In the cells differentiations into cartilage, beside the LDH isoenzymes characteristic of glycolysis, a significant LDH1 and LDH2 activity was observed. At the same site the presence of fructose-1, 6-diphosphatase-activity could be assumed, but there was no glucose-6-phosphatase activity. Glycogen synthesis proceeded in the cells of the cartilage islets and UDP-glucuronic acid-4-epimerase activity was observed in the differentiated cells. UDP-glucose dehydrogenase activity was positive in every section of the articular surface.
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PMID:Studies on cartilage formation. XX. Histochemical investigation of some enzymes of glycogen metabolsim in regenerative articular surfaces. 18 10

Enzyme histochemical study revealed that a sacrococcygeal chordoma not only was rich in oxidoreductive enzymes but also in the enzymes (phosphorylase, hexokinase, phosphoglucomutase, glucose phosphate isomerase and UDP-glucose dehydrogenase) leading to the synthesis of stromal glycosaminoglycans from glycogen. UDP-glucose dehydrogenase is particularly important in oxidizing UDP-glucose to UDP-glucuronic acid, the building block of hyaluronic acid and chondroitin sulfates. These enzymatic activities were consistent with the ultrastructural findings of abundant membrane-bound glycogen as well as large intracytoplasmic vacuoles with occasional residual glycogen particles. Furthermore, ultrastructural histochemical study using high iron diamine (HID) specifically localized the sulfated glycosaminoglycans (SG) extracellularly as well as intracellularly in distended Golgi saccules and 187-320 nm mature secretory vesicles. No HID staining was noted in the large intracytoplasmic vacuoles or rough endoplasmic reticulum. This study not only supports the hypothesis that the vacuoles of physaliphorous cells are the result of breakdown and utilization of membrane bound glycogen in the biosynthesis of SG, but also demonstrates that intracellular synthesis and storage of SG in chordoma are not in large vacuoles as previous investigators have believed.
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PMID:The nature of cytoplasmic vacuoles in chordoma cells. A correlative enzyme and electron microscopic histochemical study. 228 90

It has been found that calf eyes are an excellent source of trabecular meshwork tissue for biochemical studies. Homogenates of pooled meshwork were centrifuged at 27K X g and 1.5K X g. The high-speed supernatants produced lactate at 0.35 mumole/min/gm tissue in the presence of hexokinase-saturating concentrations of glucose (10 mM) at pH 7. The optimum pH was 7.6. In the absence of ammonia, lactate could be produced from fructose 1,6-diphosphate but not from glucose or glucose 6-phosphate. The optimum ammonia concentration was 1 to 2 mM. Lactate was produced at an even greater rate from fructose, but only poorly from sorbitol or galactose (all at 10 mM). The activity of hexokinase, glucose 6-phosphate dehydrogenase and UDPG dehydrogenase was measured. Fructokinase could not be detected. The low-speed supernatant readily oxidized succinate, malate, and glutamate at about 0.012 muAtO/min/gm tissue. The oxidative rate in vivo is estimated to be about one third of this. These results demonstrate that knowledge of the normal metabolism of calf trabecular meshwork may be obtained with relative ease, with possible important implications for understanding the disease of glaucoma.
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PMID:Metabolism of calf trabecular (reticular) meshwork. 735 Jan 29

Promotion of cell wall synthesis (from glucose) in pea (Pisum sativum) stem segments by indoleacetic acid (IAA) develops over a period of 1 to 2 hours and is comprised of a promotion of glucose uptake plus a promotion of the utilization of absorbed glucose. The effect of IAA resembles, in these and other respects, its effect on cell wall synthesis in oat coleoptile segments, but the pea system differs in not being inhibited by galactose or mannose, in involving considerably more isotope dilution by endogenous substrates, and in certain other respects.EFFECTOR INFLUENCES UPON AND TOTAL ACTIVITIES OF THE FOLLOWING ENZYMES OBTAINED FROM ETIOLATED PEA STEM SEGMENTS PRETREATED WITH OR WITHOUT IAA WERE EXAMINED: phosphoglucomutase, uridine diphosphate glucose (UDP-glucose) pyrophosphorylase, nucleoside diphosphokinase, UDP-glucose dehydrogenase, inorganic pyrophosphatase, hexokinase (particulate and soluble), and UDP-glucose-beta-1,4-glucan-glucosyl transferase (beta-glucan synthetase). The first three enzymes mentioned exhibit high activity relative to the flux in vivo, do not appear to show physiologically significant effector responses, and are concluded not to be control points. UDP-glucose dehydrogenase activity is regulated by UDP-xylose. Hexokinase is a potential control point but does not exhibit regulatory effects related to the IAA response. beta-Glucan synthetase is the only one of these enzymes with activity which is increased by treatment of tissue with IAA, and this may be responsible for the effect of IAA on wall synthesis.Assays of metabolite pools support the conclusion that stimulation of polysaccharide synthesis by IAA is due partly to changes in hexokinase reaction rate resulting from an increase in metabolic glucose pool size caused by increased glucose uptake, and partly to increased activity at the polysaccharide synthetase level.
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PMID:Regulation by auxin of carbohydrate metabolism involved in cell wall synthesis by pea stem tissue. 1665 56

1. Ethionine-treated mice showed a marked depletion in liver glycogen, a decrease of glycogen-synthetase activity, an increase in activity of glucose 6-phosphate dehydrogenase and the solubilization of phosphorylase. 2. The administration of cortisol or glucose did not alleviate these changes but the effect of ethionine was completely prevented in animals given methionine as well as ethionine. 3. The activities of the following enzymes were unchanged: hexokinase, glucokinase, glucose 6-phosphatase, phosphoglucomutase, 6-phosphogluconate dehydrogenase, UDP-glucose pyrophosphorylase, UDP-glucose dehydrogenase and pyruvate kinase.
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PMID:Depletion of glycogen synthetase and increase of glucose 6-phosphate dehydrogenase in livers of ethionine-treated mice. 1674 21