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

---

Query: EC:2.7.1.1 (hexokinase)
5,274 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This review examines the hypotheses that developmental programmed cell death in leaves is mediated (i) by sugar starvation in the leaf cells or (ii) by sugar accumulation in these cells. Experimental evidence for both hypotheses is critically discussed and found to be lacking. For example, some papers show that sugars prevent senescence of cut leaves placed in darkness, and prevent low sugar levels in the leaves. In these tests, the sugars seem to replace photosynthesis, hence the results have little relevance to leaf senescence in intact plants in the light. Low nitrogen nutrition and high light results in earlier senescence than the low nitrogen treatment alone. This is accompanied by high sugar levels in the leaves. The results have led to the idea that accumulation of sugars is the cause of the additional effect, or more generally, that sugar accumulation is always the direct cause of leaf senescence. Results from over-expressing, or knocking out, hexokinase genes tend to support the high sugar hypothesis, but pleiotropic effects confound this conclusion. In addition, several experiments show the effects of treatments on senescence without the increase in leaf sugar levels. Nonetheless, sugar levels are usually measured in whole leaves. Such an overall level does not reflect the differences in the onset of senescence between tissues and cells, and can therefore not be used as an argument for or against either of the two hypotheses. It is argued that future work should determine the time line of the concentrations of various sugars in various cells and cellular compartments, in relation to senescence processes in the same cells. Taken together, the data are not decisive. It is possible that neither of the two hypotheses is correct.
...
PMID:Is the onset of senescence in leaf cells of intact plants due to low or high sugar levels? 1845 32

Trichloroethylene (TCE), an industrial solvent, is a major environmental contaminant. Histopathological examinations revealed that TCE caused liver and kidney toxicity and carcinogenicity. However, biochemical mechanism and tissue response to toxic insult are not completely elucidated. We hypothesized that TCE induces oxidative stress to various rat tissues and alters their metabolic functions. Male Wistar rats were given TCE (1000 mg/kg/day) in corn oil orally for 25 d. Blood and tissues were collected and analyzed for various biochemical and enzymatic parameters. TCE administration increased blood urea nitrogen, serum creatinine, cholesterol and alkaline phosphatase but decreased serum glucose, inorganic phosphate and phospholipids indicating kidney and liver toxicity. Activity of hexokinase, lactate dehydrogenase increased in the intestine and liver whereas decreased in renal tissues. Malate dehydrogenase and glucose-6-phosphatase and fructose-1, 6-bisphosphatase decreased in all tissues whereas increased in medulla. Glucose-6-phosphate dehydrogenase increased but NADP-malic enzyme decreased in all tissues except in medulla. The activity of BBM enzymes decreased but renal Na/Pi transport increased. Superoxide dismutase and catalase activities variably declined whereas lipid peroxidation significantly enhanced in all tissues. The present results indicate that TCE caused severe damage to kidney, intestine, liver and brain; altered carbohydrate metabolism and suppressed antioxidant defense system.
...
PMID:Effect of trichloroethylene (TCE) toxicity on the enzymes of carbohydrate metabolism, brush border membrane and oxidative stress in kidney and other rat tissues. 1936 49

Gentamicin (GM) is an effective aminoglycoside antibiotic against severe infections but nephrotoxicity and oxidative damage limits its long term clinical use. Various strategies were attempted to ameliorate GM nephropathy but were not found suitable for clinical practice. Green tea (GT) polyphenols have shown strong chemopreventive and chemotherapeutic effects against various pathologies. We hypothesized that GT prevents GM nephrotoxicity by virtue of its antioxidative properties. A nephrotoxic dose of GM was co-administered to control and GT-fed male Wistar rats. Serum parameters and enzymes of oxidative stress, brush border membrane (BBM), and carbohydrate metabolism were analyzed. GM increased serum creatinine, cholesterol, blood urea nitrogen (BUN), lipid peroxidation (LPO) and suppressed superoxide dismutase (SOD) and catalase activities in renal tissues. Activity of hexokinase, lactate dehydrogenase increased whereas malate dehydrogenase decreased. Gluconeogenic enzymes and glucose-6-phosphate dehydrogenase were differentially altered in the cortex and medulla. However, GT given to GM rats reduced nephrotoxicity parameters, enhanced antioxidant defense and energy metabolism. The activity of BBM enzymes and transport of Pi declined by GM whereas GT enhanced BBM enzymes and Pi transport. In conclusion, green tea ameliorates GM elicited nephrotoxicity and oxidative damage by improving antioxidant defense, tissue integrity and energy metabolism.
...
PMID:Protective effect of green tea extract on gentamicin-induced nephrotoxicity and oxidative damage in rat kidney. 1942 67

A series of five glucosamine-conjugated organometallic complexes of the tricarbonyl cores of technetium-99m and rhenium were made. Glucosamine was derivatized at the C-2 nitrogen with long chain alkyl spacers linked to either pyridyl-tert-nitrogen-phenol tridentate chelates or cyclopentadienyl ligating groups. The metal complexes of the tridentate ligands were formed by refluxing with [Re(CO)(3)(H(2)O)(3)]Br, or with a base and [(99m)Tc(CO)(3)(H(2)O)(3)](+). These ligands were found to be competent chelates in binding the [(99m)Tc(CO)(3)](+) core as radiolabeling yields ranged from 87 to 93% and the resulting complexes are stable to cysteine and histidine challenges for 24 h. The cyclopentadienyl analogues were formed using a double ligand transfer reaction for the rhenium complexes and a single ligand transfer for the technetium-99m complexes. All five rhenium complexes were tested as substrates of hexokinase; two of these complexes were tested as hexokinase inhibitors and they were found to be competent inhibitors, suggesting that they may be able to interact with hexokinase. MTT cytotoxicity studies were performed and the complexes tested were found to be non-toxic to the concentrations tested (100 microM or 1 mM). GLUT-1 mediated cell uptake studies were performed on all five technetium-99m complexes, and their cell entry was found to parallel their lipophilicities, suggesting that cellular uptake is by passive diffusion and is not mediated by GLUT-1.
...
PMID:Long-chain rhenium and technetium glucosamine conjugates. 2044

The yeast protein kinases Sat4/Hal4 and Hal5 are required for the plasma membrane stability of the K(+) transporter Trk1 and some amino acid and glucose permeases. The transcriptomic analysis presented here indicates alterations in the general control of the metabolism of both nitrogen and carbon. Accordingly, we observed reduced uptake of methionine and leucine in the hal4 hal5 mutant. This decrease correlates with activation of the Gcn2-Gcn4 pathway, as measured by expression of the lacZ gene under the control of the GCN4 promoter. However, with the exception of methionine biosynthetic genes, few amino acid biosynthetic genes are induced in the hal4 hal5 mutant, whereas several genes involved in amino acid catabolism are repressed. Concerning glucose metabolism, we found that this mutant exhibits derepression of respiratory genes in the presence of glucose, leading to an increased activity of mitochondrial enzymes, as measured by succinate dehydrogenase (SDH) activity. In addition, the reduced glucose consumption in the hal4 hal5 mutant correlates with a more acidic intracellular pH and with low activity of the plasma membrane H(+)-ATPase. As a compensatory mechanism for the low glycolytic rate, the hal4 hal5 mutant overexpresses the HXT4 high-affinity glucose transporter and the hexokinase genes. These results indicate that the hal4 hal5 mutant presents defects in the general control of nitrogen and carbon metabolism, which correlate with reduced transport of amino acids and glucose, respectively. A more acidic intracellular pH may contribute to some defects of this mutant.
...
PMID:Hal4 and Hal5 protein kinases are required for general control of carbon and nitrogen uptake and metabolism. 2095 80

Ascites syndrome is still a problem for chicken industry in various parts of the world. Despite the intensive investigations of this syndrome for many years, its pathogenesis remains unclear. The objective of this study was to analyze the difference in hepatic proteomics between ascites and healthy broilers by two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS). Changes of biochemical parameters of liver and blood were also determined. The results indicated that red blood cell counts (RBC), hematocrit (HCT) and haemoglobin (HGB) of ascites broilers were significantly greater than healthy broilers. Hepatic malondialdehyde (MDA) level of ascites broilers was significantly increased, and the activity of total superoxide dismutase (T-SOD) was significantly decreased. Hepatic lactic acid (LD) level of ascitic broilers were significantly lower than healthy ones. Serum glucose and cholesterol level of ascites broilers were significantly increased, and serum globulin level was significantly decreased in ascites broilers. There was no significant difference in triglyceride (TG) and blood urea nitrogen (BUN) level. The activity of liver hexokinase (HK) and succinodehydrogenase (SDH) in ascites broilers was significantly decreased, and there was no significant difference in the activity of liver pyruvate kinase (PK) and Na+-K+-ATPase. The hepatic proteomics analysis showed that 18 proteins expression difference were identified between ascites and healthy broilers. These proteins were mainly involved in: 1) cytoskeleton; 2) glucose, lipids and amino acid metabolism; 3) cell secretion; 4) cell apoptosis; 5) signal transduction; 6) immune and inflammatory response; and 7) cellular redox homeostasis. Mitochondrial isoform phosphoenolpyruvate carboxykinase (M-PEPCK) mainly participates in gluconeogenesis of chicken liver. In conclusion, liver oxidative damage was significantly aggravated, but antioxidant capacity was decreased in cold-induced ascites broilers. Serum glucose level was significantly increased, with liver M-PEPCK expression higher in ascites broilers, which implied that some potential regulatory reagents may reduce ascites susceptibility and mortality under cold temperature by increasing liver gluconeogenesis level.
...
PMID:Changes of hepatic biochemical parameters and proteomics in broilers with cold-induced ascites. 2323 37

Epidemiological studies have demonstrated that diabetes mellitus is a serious health burden for both governments and healthcare providers. This study was hypothesized to evaluate the antihyperglycemic potential of eugenol by determine the activities of key enzymes of glucose metabolism in streptozotocin (STZ)-induced diabetic rats. Diabetes was induced into male albino Wistar rats by intraperitoneal administration of STZ (40 mg/kg body weight (b.w.)). Eugenol was administered to diabetic rats intragastrically at 2.5, 5, and 10 mg/kg b.w. for 30 days. The dose 10 mg/kg b.w. significantly reduced the levels of blood glucose and glycosylated hemoglobin (HbA1c) and increased plasma insulin level. The altered activities of the key enzymes of carbohydrate metabolism such as hexokinase, pyruvate kinase, glucose-6-phosphate dehydrogenase, glucose-6-phosphatase, fructose-1,6-bisphosphatase, and liver marker enzymes (AST, ALT, and ALP), creatine kinase and blood urea nitrogen in serum and blood of diabetic rats were significantly reverted to near normal levels by the administration of eugenol. Further, eugenol administration to diabetic rats improved body weight and hepatic glycogen content demonstrated the antihyperglycemic potential of eugenol in diabetic rats. The present findings suggest that eugenol can potentially ameliorate key enzymes of glucose metabolism in experimental diabetes, and it is sensible to broaden the scale of use of eugenol in a trial to alleviate the adverse effects of diabetes.
...
PMID:Ameliorating effect of eugenol on hyperglycemia by attenuating the key enzymes of glucose metabolism in streptozotocin-induced diabetic rats. 2407 31

Enzymic activities have been measured in cell-free extracts from nitrogen-starved cultures ofAnkistrodesmus braunii. During ten hours of nitrogenstarvation the activities of the enzymes nitrite reductase (E.C.1.6.6.4), glutamic dehydrogenase (E.C.1.4.1.4), glutamine synthetase (E.C.6.3.1.2) and urea amidolyase (E.C.3.5.1.5) were derepressed while the activities of the enzymes malate dehydrogenase (E.C.1.1.1.37) and hexokinase (E.C.2.7.1.1) remained more or less unchanged. In contrast, the photosynthetic capacity of the nitrogen-starved cultures declined rapidly and accompanying this decline were losses in the activities of ribulose diphosphate carboxylase (E.C.4.1.1.39) and triose phosphate-NADP-dehydrogenase (E.C.1.2.1.13).
...
PMID:Some effects of nitrogen-starvation on nitrogen and carbohydrate metabolism inAnkistrodesmus braunii. 2442 51

Enzymes representative of, and related to, the pentose phosphate pathway, glycolysis, and the tricarboxylic acid cycle have been demonstrated in supernatant and lamellar fractions of Anabaena cylindrica cultured in the presence of atmospheric nitrogen, ammonia, nitrite, and nitrate. Nitrogen-fixing and ammonia-assimilating algae contained essentially similar levels of most enzymes tested, with the notable exception of glyceraldehyde-3-phosphate dehydrogenase which showed increased NADPH-linked activity with concomitant diminution of NADH-linked activity when ammonia was supplied. The provision of nitrite or nitrate caused significant enhancements of glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and the related hexokinase and phosphohexoisomerase. Reduced activities of pyruvate kinase, malate dehydrogenase, phosphoenolpyruvate carboxylase, and both NADH and NADPH oxidoreductases were recorded for nitrate-grown alga.The stimulation of the pentose phosphate pathway, at the partial expense of glycolysis and the tricarboxylic acid cycle, in algae cultured with nitrite and nitrate was interpreted to be due to additional NADPH requirements imposed by induced nitrite reductase. Modification of the pyridine nucleotide linkage of glyceraldehyde-3-phosphate dehydrogenase and the oxidoreductases was attributed to diversion of reductant to nitrite and nitrate reductases and nitrogenase. The results are considered to indicate regulation of blue-green algal metabolism determined by the availability of pyridine nucleotides.
...
PMID:The influence of inorganic nitrogen supply on carbohydrate and related metabolism in the blue-green alga, Anabaena cylindrica Lemm. 2445 90

Arsenic is an environmental pollutant and its contamination in drinking water poses serious world wide environmental health threats. It produces multiple adverse effects in various tissues, including the kidney. However, biochemical mechanism and renal response to its toxic insult are not completely elucidated. We hypothesized that sodium arsenate (ARS) induces oxidative stress and alters the structure and metabolic functions of kidney. Male Wistar rats were administered ARS (10 mg/kg body weight/day), intraperitoneally daily for 10 days. ARS administration increased blood urea nitrogen, serum creatinine, cholesterol, glucose, and phospholipids but decreased inorganic phosphate, indicating kidney toxicity. The activity of brush border membrane (BBM) enzymes significantly lowered in both cortex and medulla. Activity of hexokinase, lactate dehydrogenase, glucose-6-phosphate dehydrogenases, and NADP-malic enzyme significantly increased whereas malate dehydrogenase, glucose-6-phosphatase, and fructose 1,6 bis phosphatase decreased by ARS exposure. The activity of superoxide dismutase, GSH-peroxidase, and catalase were selectively altered in renal tissues along with an increase in lipid peroxidation. The present results indicated that ARS induced oxidative stress caused severe renal damage that resulted in altered levels of carbohydrate metabolism and BBM enzymes.
...
PMID:Studies on the effect of sodium arsenate on the enzymes of carbohydrate metabolism, brush border membrane, and oxidative stress in the rat kidney. 2456 57


<< Previous 1 2 3 4 5 6 7 Next >>

---