Prpp Synthetase
Mostrando 1-11 de 11 artigos, teses e dissertações.
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1. Molecular studies of the phosphoribosyl pyrophosphate synthetases / Estudos moleculares das fosforribosil pirofosfato sintetases
Fosforribosil pirofosfato (PRPP) sintetases são enzimas de central importância em diversas vias metabólicas em todas as células. A enzima PRPP sintetase humana é constituída por um complexo composto de três subunidades catalíticas (PRSI, PRSII e PRSIII) e por proteínas homólogas de 39 e 41 kDa denominadas PRS Associated Proteins (PAPs) cuja funçã
Publicado em: 2004
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2. Regulation and Mechanism of Phosphoribosylpyrophosphate Synthetase: Repression by End Products
Phosphoribosylpyrophosphate (PRPP) synthetase participates in the biosynthesis in bacteria of purine nucleotides, pyrimidine nucleotides, tryptophan, and histidine. The regulation of the synthesis of PRPP synthetase in Salmonella typhimurium was studied. Addition of end products to the growth medium, singly or in combination, resulted in small decreases in t
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3. Mutation in the phosphoribosylpyrophosphate synthetase gene (prs) that results in simultaneous requirements for purine and pyrimidine nucleosides, nicotinamide nucleotide, histidine, and tryptophan in Escherichia coli.
A mutant of Escherichia coli harboring a temperature-labile phosphoribosylpyrophosphate (PRPP) synthetase was characterized. Despite the lack of a detectable PRPP pool or PRPP synthetase activity at 40 degrees C, the strain was fully viable at this temperature as long as guanosine, uridine, histidine, tryptophan, and nicotinamide mononucleotide were all adde
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4. Mutant feedback-resistant phosphoribosylpyrophosphate synthetase associated with purine overproduction and gout. Phosphoribosylpyrophosphate and purine metabolism in cultured fibroblasts.
We have reported previously two siblings with gout and uric acid lithiasis associated with excessive purine production. In the erythrocytes of these patients, phosphoribosylpyrophosphate (PRPP) synthetase exhibited resistance to feedback-inhibition by normal cell constituents such as guanosine-5'-diphosphate (GDP) and adenosine-5'-diphosphate (ADP), resultin
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5. Effect of treatment on erythrocyte phosphoribosyl pyrophosphate synthetase and glutathione reductase activity in patients with primary gout.
The activities of erythrocyte phosphoribosyl pyrophosphate (PRPP) synthetase and glutathione reductase (GTR) were studied in 26 patients with primary gout who were receiving no treatment or treatment with either allopurinol or azapropazone, and compared with the activity in a group of healthy controls. The activity of PRPP synthetase was significantly higher
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6. Selective expression of phosphoribosylpyrophosphate synthetase superactivity in human lymphoblast lines.
Phenotypic expression of 5-phosphoribosyl 1-pyrophosphate (PRPP) synthetase superactivity was examined in lymphoblast lines derived from six unrelated male patients. Fibroblasts from these individuals have increased rates of PRPP and purine nucleotide synthesis and express four classes of kinetic derangement underlying enzyme superactivity: increased maximal
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7. prsB is an allele of the Salmonella typhimurium prsA gene: characterization of a mutant phosphoribosylpyrophosphate synthetase.
The Salmonella typhimurium prsB mutation was previously mapped at 45 min on the chromosome, and a prsB strain was reported to produce undetectable levels of phosphoribosylpyrophosphate (PRPP) synthetase activity and very low levels of immunologically cross-reactive protein in vitro (N.K. Pandey and R.L. Switzer, J. Gen. Microbiol, 128:1863-1871, 1982). We ha
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8. Ribose metabolism and nucleic acid synthesis in normal and glucose-6-phosphate dehydrogenase-deficient human erythrocytes infected with Plasmodium falciparum.
The metabolism of pentose-phosphate was investigated in Plasmodium falciparum-infected normal and glucose-6-phosphate dehydrogenase (G6PD)-deficient human red blood cells in vitro. 5'-Phosphoribosyl-1-pyrophosphate (PRPP) content of infected normal red blood cells was increased 50-60-fold at the parasite trophozoite growth stage over that of uninfected cells
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9. De novo synthesis of purine nucleotides in human peripheral blood leukocytes. Excessive activity of the pathway in hypoxanthine-guanine phosphoribosyltransferase deficiency.
Human peripheral blood leukocytes were studied for the presence and the regulatory properties of the pathway of de novo synthesis of purine nucleotides. The cells were found to incorporate the labeled precursors formate and glycine into purines. The rate of [14C]-formate incorporation was decreased by several compounds known to inhibit purine synthesis by af
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10. Enzymes of Purine Biosynthesis and Catabolism in Glycine max1: I. COMPARISON OF ACTIVITIES WITH N2 FIXATION AND COMPOSITION OF XYLEM EXUDATE DURING NODULE DEVELOPMENT
During the period examined from 12 to 63 days after planting, the ureides, allantoin and allantoic acid, were the predominant nitrogenous solutes in the xylem exudate of soybeans (Glycine max [L.]) growing solely on symbiotically fixed nitrogen, accounting for approximately 60% and greater than 95% of the total nitrogen in the xylem exudate before and after
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11. Characterization of a Feedback-Resistant Phosphoribosylpyrophosphate Synthetase from Cultured, Mutagenized Hepatoma Cells That Overproduce Purines
A clone of cells in which the regulation of purine metabolism is genetically altered was selected and isolated from chemically mutagenized HTC cells (a line of rat hepatoma cells in continuous culture). The clone, designated MAU V, was selected for increased ability to salvage exogenous purines by isolating it in medium containing methylmercaptopurine ribonu