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)

All six enzymes of pyrimidine biosynthesis de novo have been detected in homogenates of the culture promastigote form of Leishmania mexicana amazonensis, the blood trypomastigote form of Trypanosoma brucei and the culture epimastigote, blood trypomastigote and intracellular amastigote forms of Trypanosoma cruzi. Dihydroorotate dehydrogenase is mitochondrial in mammals, but the isofunctional enzyme, dihydroorotate oxidase was found to be cytoplasmic, whereas orotate phosphoribosyltransferase and orotidine-5'-phosphate decarboxylase, which are cytoplasmic in mammals, were found to be particulate. Analysis by isopycnic sedimentation in sucrose showed that both particulate enzymes co-sedimented with glycosomal-(microbody-)marker enzymes such as hexokinase. Electron microscopy indicated that fractions containing these activities consisted essentially only of microbodies. It is concluded therefore that these enzymes are associated with glycosomes. Kinetic studies with intact glycosomal preparations suggested that there was no membrane barrier between 5-phosphoribose 1-pyrophosphate (P-Rib-PP) and orotate phosphoribosyltransferase, indicating either that the active site of this enzyme is probably on the outside of the glycosome or that the glycosome may have an efficient transport site for P-Rib-PP. Not all the UMP salvage enzymes assayed were detected. No uridine kinase activity was found in any of the species investigated, suggesting that uridine salvage might be routed via a uridine phosphorylase and uracil phosphoribosyltransferase. In agreement with this suggestion, these latter activities were detected in all organisms tested except the intracellular amastigote form of T. cruzi, where uracil phosphoribosyltransferase appeared absent. All the UMP salvage enzymes investigated occurred in cytoplamic fractions.
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PMID:UMP synthesis in the kinetoplastida. 675 42

We studied on the proteomic characteristics of Toxoplasma gondii KI-1 tachyzoites which were originally isolated from a Korean patient, and compared with those of the well-known virulent RH strain using 2-dimensional electrophoresis (2-DE), mass spectrometry, and quantitative real-time PCR. Two-dimensional separation of the total proteins isolated from KI-1 tachyzoites revealed up to 150 spots, of which 121 were consistent with those of RH tachyzoites. Of the remaining 29 spots, 14 showed greater than 5-fold difference in density between the KI-1 and RH tachyzoites at a pH of 5.0-8.0. Among the 14 spots, 5 from the KI-1 isolate and 7 from the RH strain were identified using MALDI-TOF mass spectrometry and database searches. The spots from the KI-1 tachyzoites were dense granule proteins (GRA 2, 3, 6, and 7), hypoxanthine-guanine-xanthine phosphoribosyltransferase (HGRPTase), and uracil phosphoribosyltransferase (UPRTase). The spots from the RH strain were surface antigen 1 (SAG 1), L-lactate dehydrogenase (LDH), actin, chorismate synthase, peroximal catalase, hexokinase, bifunctional dihydrofolate reductase-thymidylate synthase (DHTR-TS), and nucleoside-triphosphatases (NTPases). Quantitative real-time PCR supported our mass spectrometric results by showing the elevated expression of the genes encoding GRA 2, 3, and 6 and UPRTase in the KI-1 tachyzoites and those encoding GRA 7, SAG 1, NTPase, and chorismate synthase in the RH tachyzoites. These observations demonstrate that the protein compositions of KI-1 and RH tachyzoites are similar but differential protein expression is involved in virulence.
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PMID:Proteomic analysis of Toxoplasma gondii KI-1 tachyzoites. 2087 97