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 marked reduction of granulocyte chemotactic function accompanies the storage of granulocyte concentrates. Since chemotaxis is energy dependent, we studied energy metabolism in stored neutrophils. We and others have reported that stored neutrophils have a defect in their energy metabolism. We found that defective adenosine triphosphate maintenance in stored neutrophils was occult in resting cells, but was unmasked by an energy-intensive stimulus, phagocytosis. In studies reported here, we sought to determine if defective adenosine triphosphate maintenance during granulocyte storage was related to altered glycolytic enzyme activity. We studied the activity of glycolytic enzymes in fresh and stored, resting and stimulated (opsonized zymosan) neutrophils. The following enzyme activities showed no major changes during storage, in resting or stimulated neutrophils: hexokinase, phosphofructokinase, aldolase, glucose phosphate isomerase, triose phosphate isomerase, glyceraldehyde phosphate dehydrogenase, phosphoglycerate kinase, phosphoglyceromutase, enolase, lactate dehydrogenase, glucose-6-phosphate dehydrogenase, glutathione reductase, and glutathione peroxidase. In contrast, pyruvate kinase activity consistently increased during storage. In 6 units, pyruvate kinase activity increased by 75 percent after 24 hours of storage at room temperature and by 198 percent after 48 hours. The storage-associated increase in pyruvate kinase activity was not inhibited by cycloheximide. Stimulation of neutrophils by phagocytosis of opsonized zymosan also produced striking increases in the pyruvate kinase activity of both fresh and stored cells. Additional studies indicated that the increases in pyruvate kinase activity observed during storage and after phagocytosis were associated with an increase in the availability of pyruvate kinase activity in the supernatant fraction of neutrophil sonicates. Total pyruvate kinase activity in sonicates of neutrophils was unchanged by storage or particle ingestion.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Glycolytic enzymes of stored granulocytes. 632 24

Evidence is presented for the occurrence of glycosomes (organelles resembling peroxisomes) in four major species of Leishmania (viz. L. major, L.m. mexicana, L. b. braziliensis and L. donovani), based on latency as well as differential and isopycnic centrifugation studies. The enzymes involved in glycolysis; (hexokinase, phosphoglucose isomerase, phosphofructokinase, fructose-1,6-bisphosphate aldolase, triosephosphate isomerase, glyceraldehyde-phosphate dehydrogenase and phosphoglycerate kinase); glycerol metabolism (sn-glycerol-3-phosphate dehydrogenase and glycerol kinase); carbon dioxide fixation (phosphoenolpyruvate carboxykinase and possibly malate dehydrogenase); together with an enzyme involved in the beta-oxidation of fatty acids (3-beta-hydroxybutyryl coenzyme A dehydrogenase); a key enzyme in the synthesis of ether lipids (dihydroxyacetone phosphate acyltransferase) as well as the ADP utilising enzyme adenylate kinase, were all found associated, at least in part, with a subcellular organelle which had a buoyant density in sucrose gradients of 1.21 to 1.24 g cm-3. Little variance in enzyme composition was found between the different species of Leishmania or in comparison with other members of the Trypanosomatidae, supporting the unifying principle that glycosomes are a unique characteristic of this family. The occurrence of important catabolic, anabolic and anaplerotic pathways in the glycosomes of Leishmania renders them prime targets for chemotherapy.
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PMID:The occurrence of glycosomes (microbodies) in the promastigote stage of four major Leishmania species. 644 18

The role of metabolic energy in cell maturation-associated loss of membrane functions has been studied using sheep reticulocytes incubated in vitro at 37 degrees C for periods up to 41 hours. ATP either was maintained with glucose, adenosine plus inosine or depleted with 2-deoxyglucose plus arsenate. Two membrane transport systems were studied: Na+-dependent glycine transport and the sodium pump, estimated from the number of specific [3H] ouabain binding sites per cell. Although both transport systems decreased during maturation, the decrease was much less in ATP-depleted cells compared to ATP-replete cells. The phenomenon is relatively specific: not all maturation-associated changes are similarly affected. Thus, the decreases in activity of the cytoplasmic enzymes glucose-6-phosphate dehydrogenase, hexokinase and phosphoglucose isomerase were not prevented by energy depletion. It is concluded that the loss of certain functions during reticulocyte maturation is retarded by metabolic depletion.
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PMID:The role of metabolic energy in the maturation-associated loss of reticulocyte membrane transport. 650 12

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

Highly purified glycosomes were isolated from Trypanosoma brucei bloodstream forms and cultured procyclic trypomastigotes. A comparison of the specific activities of glycosomal enzymes revealed that glycosomes from insect stages had decreased levels of hexokinase, phosphoglucose isomerase, phospho-fructokinase, fructose-bisphosphate aldolase, glyceraldehyde-phosphate dehydrogenase and phosphoglycerate kinase, but contained increased levels of adenylate kinase, malate dehydrogenase and phosphoenolpyruvate carboxykinase. Glycosomes from bloodstream forms were almost totally devoid of the latter two activities. Comparison of the two types of glycosomes by sodium dodecylsulphate-polyacrylamide gel electrophoresis revealed that bloodstream form glycosomes contained 3 prominent polypeptides (64, 46 and 40 kDa) which were hardly detectable in insect stage glycosomes, whereas the latter contained 3 insect stage specific bands with molecular weight of 34 000, 61 000 and 77 000 and 4 additional bands with molecular weights between 94 000 and 110 000. Both types of glycosome contained the phospholipids phosphatidylcholine and phosphatidylethanolamine. Insect stage glycosomes contained in addition also phosphatidylinositol and some phosphatidylserine.
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PMID:A comparison of the glycosomes (microbodies) isolated from Trypanosoma brucei bloodstream form and cultured procyclic trypomastigotes. 674 87

Recently, it has been reported that paromomycin sulfate has marked anthelmintic efficacy against tapeworm infections in man. In the present study this drug was used in the treatment of 14 cases of diphyllobothriasis latum and 1 case of taeniasis saginata. Also, the actions of paromomycin sulfate on Diphyllobothrium ditremum and D. erinacei were examined pharmacologically using Magnus apparatus and biochemical methods. The results obtained were as follows. For the treatment, a total of 50 mg/kg of paromomycin sulfate divided into 2 doses was given orally at intervals of 30 minutes. Two hours after medication, 20 g of magnesium sulfate dissolved in 200--300 ml of water was given as purgative. One or 2 worms were found in the stools of 11 cases with D. latum and 1 case with T. saginata within 24 hours after medication, but scolex was found in only 2 of them. All cases were negative for the eggs or segments in stool examinations at 1 and 3 months after treatment. Except 1 case complained mild and transient vomiting no side effects were noticed. All cases showed no abnormality in blood examination, liver function test and urinalysis. Both of the proglottids of D. ditremum and D. erinacei showed muscle relaxation in Tyrode solution containing 10(-4) g/ml of paromomycin sulfate. In D. ditremum the recovery of muscle tonus was observed within 10--15 minutes after affection of this drug, while the persistence of muscle relaxation was seen in D. erinacei. The activity of phosphoglucose isomerase was slightly inhibited by 10(-3) M paromomycin sulfate while those of hexokinase, phosphofructokinase and glucose-6-phosphate dehydrogenase were not inhibited. In phosphoenolpyruvate-succinate pathway, the activity of fumarate reductase was slightly inhibited 10(-3) M paromomycin sulfate while those of phosphoenolpyruvate carboxykinase and malate dehydrogenase were not inhibited.
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PMID:[Efficacy of paromomycin sulfate against human cestodiasis and its pharmacological action on tapeworm in vitro]. 687 66

Clones of 32 strains of Trichomonas vaginalis isolated from patients attending a venereal diseases clinic were compared among themselves and with authentic Pentatrichomonas hominis on the basis of their isoenzyme patterns for eight enzymes by thin-layer starch-gel electrophoresis. The enzymes examined were: glucose phosphate isomerase (GPI); phosphoglucomutase (PGM); malic enzyme (NADP+) (ME); hexokinase (HK); malate dehydrogenase (NAD+) (MDH); glucose-6-phosphate dehydrogenase (G6PD); aldolase (ALD); and lactate dehydrogenase (LDH). From the isoenzyme patterns of four enzymes (LDH, MDH, HK, and GPI) the strains of T vaginalis could be divided clearly into five groups. PGM showed differences in only one strain, while two other enzyme patterns (ME and ALD) were the same for all the strains of T vaginalis tested. All isolates were clearly distinguishable from P hominis. Although G6PD patterns were not sharp some differences were evident among T vaginalis strains.
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PMID:Isoenzyme characterisation of Trichomonas vaginalis. 698 Jun 85

The purification of an enzyme is described, a protease, from human erythrocytes which degrades insulin with a high specificity at physiological hormone concentrations. Since the enzyme contains free sulfhydryl groups, affinity chromatography on organomercuri-Sepharose proved to be applicable as a valuable step in the isolation procedure. The purification factor amounted to approx. 6000, the yield to 8%. 1mg of purified enzyme was capable of degrading 50 pmol of insulin/min into trichloroacetic acid-soluble split products. The purified insulin-degrading enzyme was shown to be homogeneous, as demonstrated by gel chromatography, gel electrophoresis and isoelectric focusing. The isoelectric points was at pH 5.8. The molecular weight of nativ enzyme was estimated by gel chromatography and gel electrophoresis and found to be about 150 000-160 000, consisting of 4 subunits. Degradation products of insulin eluted from a Biogel P 30 column are smaller than the A-chain of the hormone, suggesting the activity of a protease. The enzyme appears to be specific for insulin in that it does not degrade other peptide hormones such as growth hormone, prolactin, or thyroid-stimulating hormone. Furthermore, the enzyme does not inactivate enzymes such as lactate dehydrogenase, aldolase, fructose 1,6-bisphosphatase, hexosephosphate isomerase or hexokinase.
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PMID:Purification to homogeneity of an insulin-degrading enzyme from human erythrocytes. 699 71

Washing of bull and ram spermatozoa resulted in significant losses of lactic dehydrogenase (LDH) and glucose phosphate isomerase (GPI) from the cell suspensions. Re-suspension of washed bull spermatozoa caused an immediate release of enzymes from the cells. Preincubation of washed ram spermatozoa with 0.025% formaldehyde increased GPI levels but decreased LDH concentration in the extracellular fluid while hexokinase release was unaffected. Varying the incubation temperature between 20 and 37 degrees C affected extracellular LDH and GPI levels. It is suggested that enzyme release from spermatozoa may occur in the absence of any apparent cellular damage.
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PMID:Studies on leakage of enzymes from washed bull and ram spermatozoa. 701 29

1. Activities of 20 red cell enzymes were compared in 8 normal female Ovis Aries, in a serially bled ewe followed by 243 days, and in young and old red cell populations separated by density gradient centrifugation. 2. These comparisons indicate that the erythrocyte enzymes which show significant changes with cell age are glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, hexokinase, phosphoglucose isomerase, lactate dehydrogenase, glutathione reductase, enolase and phosphoglycerate kinase. 3. The usefulness of these data in interpretation of enzyme activities from fetal Ovis Aries is discussed.
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PMID:Erythrocyte enzymes in Ovis aries. Effect of cell age. 706 Mar 50


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