Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.5 (5'-nucleotidase)
 3,167 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Whole sheets of plasma membrane, each with their attached flagellum, were purified from Trypanosoma brucei. The method devised for their isolation included a new technique of cell breakage that used a combination of osmotic stress followed by mechanical sheer and avoided the problem of extreme vesiculation as well as the trapping of organelles in cell 'ghosts'. The purified membranes all contained the pellicular microtubular array. The antigenic surface coat was completely released from the plasma membrane during the isolation procedure. The membranes had a very high cholesterol/phospholipid ratio (1.54). A large proportion (42%) of the cellular DNA was recovered in the plasma-membrane fraction unless a step involving deoxyribonuclease treatment, which decreased the DNA content to less than 13%, was included before secrose-density gradient centrifugation. This step also aided the separation of plasma membranes from other cellular components. The ouabain-sensitive Na+ + K+-stimulated adenosine triphosphatase and adenylate cyclase co-purified with the plasma membranes. Although 5'-nucleotidase was thought to be a plasma-membrane component, it was easily detached from the membrane. The purified membranes were essentially free of L-alanine-alpha-oxoglutarate aminotransferase, L-asparte-alpha-oxoglutarate aminotransferase, malate dehydrogenase, oligomycin-sensitive adenosine triphosphatase, glucose 6-phosphatase, Mg2+-stimulated p-nitrophenyl phosphatase and catalase.
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PMID:The isolation and partial characterization of the plasma membrane from Trypanosoma brucei. 48 94

Micromolar concentrations of GDP or GTP stimulate protein synthesis by isolated yeast mitochondria 3- to 10-fold even if alpha-ketoglutarate and an ATP-regenerating system are present. No stimulation is observed with GMP, UTP, CTP, TTP, and the nonhydrolyzable GTP analogues guanyl(beta, gamma-methylene) diphosphate and guanyl imidodiphosphate. This stimulatory effect of exogenously added guanyl nucleotides may answer the long standing question why protein synthesis by isolated mitochondria is so slow. It can also explain previous reports by two other laboratories that a high speed supernatant from yeast cells stimulates protein synthesis by isolated mitochondria. The supernatant contains nondialyzable GMP which is converted to GDP under the conditions used for assaying mitochondrial protein synthesis. The stimulatory effect of high speed supernatants is abolished by 5'-nucleotidase (which degrades GMP) or by trypsin (which destroys supernatant protein(s) necessary for converting GMP to GDP). No evidence was obtained that the stimulatory effect of high speed supernatants was caused by precursors to cytoplasmically made cytochrome c oxidase subunits.
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PMID:Stimulation of in vitro mitochondrial protein synthesis by yeast cytoplasmic extracts is caused by guanyl nucleotides. 624 10

HTK (histidine-tryptophane-ketoglutarate) organ preservation solution has been shown to be effective in human kidney transplantation, but the efficacy of HTK for extended liver preservation has not been determined. In this study, canine livers were preserved in HTK and compared with livers preserved in University of Wisconsin solution. First, the right and left liver lobes in dogs were flushed separately with cold HTK and UW, respectively, according to a double-flush method. After splitting the liver, the right and left lobes were stored at 4 degrees C in either solution for 24 hr and 48 hr and assessed microscopically for parenchymal cell swelling, and enzyme histochemically for 5'-nucleotidase (5'-NT) as a marker of ischemic liver injury. Unlike livers preserved in UW (n = 5), HTK-preserved livers (n = 5) showed progressive parenchymal cell swelling after 24-hr and 48-hr storage. The 5'-NT scores in HTK livers were lower than in UW livers, indicating increased storage injury (0-5% and 66-85% in HTK- and UW-preserved livers, respectively, after 48-hr storage). Second, graft function was tested in an orthotopic liver transplantation model in the dog. Whole livers were flushed in situ with cold HTK or UW and stored at 4 degrees C for 24 hr or 48 hr. Liver grafts stored in HTK were not washed out prior to reflow in the recipient, in contrast to grafts stored in UW. Livers preserved for 24 hr using HTK showed life-supporting function after transplantation (n = 5, survival 12 hr-8 days). All grafts preserved for 48 hr in HTK did not function (n = 5, survival < 10 hr). UW-preserved grafts all functioned after 24-hr storage (n = 5, survival > 6 days), as well as after 48-hr storage (n = 6, survival > 6 days). Peak serum glutamic oxaloacetic transaminase (SGOT) values after transplantation of 24-hr and 48-hr HTK-preserved livers did not differ from peak SGOT values of UW-preserved livers after similar preservation times. In conclusion, UW solution is more effective than HTK solution in extended preservation of canine liver grafts: 24-hr storage of livers preserved with HTK solution is feasible, whereas 48-hr storage results in a nonfunctioning graft.
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PMID:Preservation of canine liver grafts using HTK solution. 831 May 2