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

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

THe level of enzyme activity, the enzyme thermostability profile, and the isozyme electrophoretic pattern were determined in young and old erythrocytes from newborn infants and adults and in samples from adult individuals with increased reticulocyte counts. Cord blood samples had higher levels of enzymatic activity for 12 of the 14 enzymes measured, adenylate kinase and phosphoglucomutase being the exceptions. The largest differences in activity between newborns and adults were for glutamic oxaloacetic transaminase, hexokinase, glucose 6-phosphate dehydrogenase, and glutathione reductase, while glutamic oxaloacetic transaminase and pyruvate kinase showed the largest differences between young and old cells. The levels of activity of glutathione reductase, adenylate kinase, phosphoglucomutase, lactate dehydrogenase, phosphoglycerokinase, and glucose phosphate isomerase in cord blood samples suggest the regulation of expression of these enzymes is different in fetal erythrocytes than in erythrocytes from an adult. Differences in the thermostability profile of enzymes from cells from different sources and/or of different ages were noted for 5 of 9 enzymes. No unique electrophoretically identifiable fetal isozymes were observed, although differences in isozyme distribution and staining intensity associated with cell source and/or cell age were noted for many of the 23 enzymes examined. Many of these differences in enzyme characteristics have the potential to be confused with genetic alterations in enzyme structure and function.
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PMID:Characteristics of enzymes of erythrocytes from newborn infants and adults: activity, thermostability, and electrophoretic profile as a function of cell age. 730 4

Isoenzyme typing was used to study a number of oocyst isolates of Cryptosporidium parvum from different geographical locations and of human or animal origin. All isolates showed identical enzyme motility when glucose phosphate isomerase (GPI; 23 isolates tested) or lactate dehydrogenases (LDH; 20 isolates tested) was assayed. However, two isoenzyme forms were observed with phosphoglucomutase (PGM; 9 animal isolates showed one form, while 8/9 human isolates showed a second form) and hexokinase (HK; 4 human isolates showed one form and 6 animal isolates showed a second form). Thus, PGM and HK each exhibit 2 isoenzymes corresponding to 2 parasite populations associated with separate hosts. The data from this study, plus supportive evidence obtained by different methods and by independent researchers, lend support to the hypothesis that separate cycles of transmission of C. parvum may exist within human and animal hosts.
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PMID:Differentiation between human and animal strains of Cryptosporidium parvum using isoenzyme typing. 788 31

A method was developed to measure the activities of enzymes in extracts from single human preimplantation embryos. The method permits the analysis of two enzymes plus appropriate controls in an extract from a single embryo, and was used to investigate the control of energy metabolism during the development of human embryos from the two-cell to the blastocyst stage. Hexokinase (HK), 6-phosphofructokinase (PFK), pyruvate kinase (PK), fructose-1,6-diphosphate aldolase (ALD), glucose phosphate isomerase (GPI), lactate dehydrogenase (LDH), glucose-6-phosphate dehydrogenase (G6PDH) and 2-oxoglutarate dehydrogenase (ODH) were all detectable, whereas glycogen phosphorylase (GP) was not. The enzyme activities of ODH, PFK, LDH, PK, GPI and G6PDH, averaged over all stages of development from the two-cell to blastocyst stage (days 2-6 after insemination), were 3.5, 6.6, 15, 69, 73 and 87 times greater than HK, respectively. The activity of ALD was very similar to that of HK. The activities of ALD, GPI, PFK, PK and LDH showed no significant variation with stage of development, although the activity of GPI fell significantly from the four-eight cell to the eight-sixteen cell stage (P < 0.05). HK activity decreased from the two-eight cell to the eight-sixteen cell (P < 0.05), and increased significantly from the eight-sixteen cell to the blastocyst stage (P < 0.01). The overall relationship between hexokinase activity and stage approached significance (P = 0.059, one-way analysis of variance). The activity of G6PDH decreased significantly with development (P < 0.001, one way analysis of variance).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Activity of enzymes of energy metabolism in single human preimplantation embryos. 828 48

The zymodemes, electrophoretic patterns of hexokinase, phosphoglucomutase and glucose phosphate isomerase isoenzymes, have been widely used to determine the pathogenicity of Entamoeba histolytica isolates. Although pathogenic and nonpathogenic forms of E. histolytica differ clearly in sequences of many homologous genes, a conversion between pathogenic and nonpathogenic zymodemes has been reported by several laboratories. To approach the question what might be the basis for the observed conversion, we examined the molecular biology of the hexokinase (ATP:D-hexose 6-phosphotransferase, EC 2.7.1.1) isoenzymes in pathogenic E. histolytica. We isolated two different cDNAs pHXK1 and pHXK2 coding for polypeptides with significant sequence similarity to hexokinases and deduced molecular masses of 49.8 kDa and 49.4 kDa. The two hexokinase sequences differed by 11% on the amino acid and by 8% on the nucleotide level. Expression of the cDNAs in Escherichia coli as nonfusion proteins gave two polypeptides with hexokinase activity. The recombinant Hxk1 and Hxk2 polypeptides comigrated with the more basic and more acidic isoforms of pathogenic amoebae in starch gel electrophoresis, as well as in low and high resolution isoelectric focussing gels. This identified the observed hexokinase isoenzymes of pathogenic E. histolytica as the products of two genes, hxk1 and hxk2.
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PMID:Molecular analysis of two hexokinase isoenzymes from Entamoeba histolytica. 857 26

Samples of two Phlebotomus sergenti natural populations from San Juan (Tenerife), representing the western edge of the distribution area of this species, and Axos (Crete) were collected. The morphological comparison showed marked differences in the lengths of parts of the male genitalia, female pharynx, and spermathecae. The isoenzyme study revealed characteristic monomorphic phenotypes for glucose phosphate isomerase, hexokinase, and phosphoglucomutase in the Canarian specimens as compared with the Cretan population. These results confirm the heterogeneity of P. sergenti and indicate the utility of a systematic double approach for a revision of this taxon.
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PMID:Phlebotomus sergenti parrot, 1917: morphological and isoenzymatic comparisons of two natural populations from Tenerife (Canary Islands, Spain) and Crete (Greece). 882 45

Studies on human and murine isolates of Schistosoma mansoni, from Richard-Toll, Senegal, were carried out by isoelectric focusing in polyacrylamide gels. Seven enzyme systems; lactate dehydrogenase (LDH), malate dehydrogenase (MDH), glucose-6-phosphate dehydrogenase (G6PD), acid phosphatase (AcP), hexokinase (HK), glucose phosphate isomerase (GPI), and phosphoglucomutase (PGM), were used to compare the two isolates. All systems tested, apart from LDH, were found to be polymorphic for both isolates. Interestingly, one phenotype is more frequent than the remainder. The results show that there is no significant genetic variation between the S. mansoni isolates from man and the rodents, Arvicanthis niloticus and Mastomys huberti.
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PMID:Comparison of human and murine isolates of Schistosoma mansoni from Richard-Toll, Senegal, by isoelectric focusing. 919 7


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