Adenine Phosphoribosyltransferase
Mostrando 1-12 de 127 artigos, teses e dissertações.
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1. Adenina fosforibosiltransferase de Schistosoma mansoni: proposta de detalhamento do mecanismo catalítico por dinâmica molecular / Adenine phosphoribosyltransferase from Schistosoma mansoni: insights into the catalytic mechanism via molecular dynamics
A Adenina Fosforibosiltransferase (APRT E.C. 2.4.2.7) pertence à família de enzimas Fosforibosil Transferases (PRTase) do Tipo I , que catalisa a conversão reversível de Adenina e 5-fosfo-α-D-ribose-1-difosfato (PRPP) em difosfato e adenosina monofosfato, um importante precursor energético da célula. A APRT integra a via de salvação de purinas,
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 12/08/2011
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2. Estudos estruturais e correlação com a síndrome urolitíase de mutantes da adenina fosforribosiltransferase humana / Structural studies and correlation with urolithiasis syndrome of mutants from human adenine phosphoribosyltransferase
A 2,8-DHA Urolitíase é uma doença resultante de uma desordem hereditária que leva a deficiência de atividade da enzima APRT do grupo das PRTases. Até o momento, foram encontradas 18 mutações em pacientes, das quais 7 são missense. O presente trabalho dedica-se ao estudo funcional e estrutural dessas 7 mutações e da deleção ΔF173. Construç
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 19/04/2011
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3. Assignment of the Gene for Adenine Phosphoribosyltransferase to Human Chromosome 16 by Mouse-Human Somatic Cell Hybridization
A series of mouse-human hybrids was prepared from mouse cells deficient in adenine phosphoribosyltransferase (EC 2.4.2.7) and normal human cells. The hybrids were made in medium containing adenine and alanosine, an antimetabolite known to inhibit de novo adenylic acid biosynthesis. The mouse cells, unable to utilize exogenous adenine, were killed in this med
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4. Genetic instability at the adenine phosphoribosyltransferase locus in mouse L cells.
Resistance to adenine analogs such as 2,6-diaminopurine occurs at a rate of approximately 10(-3) per cell per generation in mouse L cells. This resistance is associated with a loss of detectable adenine phosphoribosyltransferase activity. Other genetic loci in L cells have the expected mutation frequency (approximately 10(-6)). Transformation of L cell mutan
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5. Adenine phosphoribosyltransferase-deficient mice develop 2,8-dihydroxyadenine nephrolithiasis.
Adenine phosphoribosyltransferase (APRT) deficiency in humans is an autosomal recessive syndrome characterized by the urinary excretion of adenine and the highly insoluble compound 2,8-dihydroxyadenine (DHA) that can produce kidney stones or renal failure. Targeted homologous recombination in embryonic stem cells was used to produce mice that lack APRT. Mice
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6. Inhibition of De Novo Purine Biosynthesis and Interconversion by 6-Methylpurine in Escherichia coli
The inhibition of Escherichia coli strain B and strain W-11 by 6-methylpurine depended on the formation of 6-methylpurine ribonucleotide by the action of adenine phosphoribosyltransferase (AMP: pyrophosphate phosphoribosyltransferase, EC 2.4.2.7). 6-Methylpurine ribonucleotide inhibited the de novo synthesis of purines, presumably via pseudofeedback inhibiti
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7. Nature of 6-methylpurine inhibition and characterization of two 6-methylpurine-resistant mutants of Neurospora crassa.
6-Methylpurine, an analog of adenine, inhibits the growth of Neurospora crassa. From kinetic studies it was found that 6-methylpurine is converted to its nucleotide form by adenine phosphoribosyltransferase (EC 2.4.2.7), and inhibits the de novo purine biosynthesis. Adenine relieves the growth inhibition caused by 6-methylpurine, whereas hypoxanthine is not
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8. The influence of a (GT)29 microsatellite sequence on homologous recombination in the hamster adenine phosphoribosyltransferase gene.
Several DNA sequence elements are thought to stimulate homologous recombination, illegitimate recombination, or both in mammalian cells. Some are implicated by their recurrence around rearrangement breakpoints, others by their effects on recombination of extrachromosomal plasmids. None of these sequences, however, has been tested on the chromosome in a defin
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9. A moveable 5' splice site in adenine phosphoribosyltransferase genes of Drosophila species.
In two distantly related Drosophila species, the use of alternate 5' splice sites to process an intron in pre-mRNA from homologous adenine phosphoribosyltransferase (APRT)-encoding genes led to RNAs encoding nonfunctional peptides in addition to APRT. The production of aberrantly spliced transcripts as a normal feature of gene expression supports a general m
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10. Adenine aminohydrolase: occurrence and possible significance in trypanosomid flagellates.
Adenine aminohydrolase (EC 3.5.4.2) from four species of Leishmania and from Crithidia fasciculata was examined for specific activities, affinity for substrate (adenine), and stability to heat. All were found to be strongly and non-competitively inhibited by both coformycin and deoxycoformycin, two tight-binding inhibitors of adenosine deaminase (adenosine a
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11. Isolation of a Chinese Hamster Cell Mutant with Low Intracellular Phosphoribosylpyrophosphate Concentration
A tritium-adenine suicide procedure was used to select for mutants with reduced uptake of adenine from a population of Chinese hamster V79 cells mutagenized with ethyl methane sulfonate. In one of the mutant lines isolated, designated KC62, the uptake of adenine, hypoxanthine, and guanine was reduced by approximately 70%. The specific activities, Km values,
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12. DNA-mediated transfer of the adenine phosphoribosyltransferase locus into mammalian cells.
In this report, we demonstrate the feasibility of transforming mouse cells deficient in adenine phosphoribosyltransferase (aprt; AMP:pyrophosphate phosphoribosyltransferase, EC 2.4.2.7) to the aprt+ phenotype by means of DNA-mediated gene transfer. Transformation was effected by using unfractionated high molecular weight genomic DNA from Chinese hamster, hum