Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.4.2.7 (adenine phosphoribosyltransferase)
 692 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Complete adenine phosphoribosyltransferase (APRT) deficiency causes 2,8-dihydroxyadenine urolithiasis. In previous reports, analysis of the kinetic properties of APRT from APRT-deficient Japanese subjects revealed strikingly similar abnormalities suggesting a distinct "Japanese-type" mutation. In this paper, we report studies of 11 APRT-deficient lymphoblast cell lines. Nucleotide sequence analysis of APRT genomic DNA from WR2, a Japanese-type homozygote, identified a T to C substitution in exon 5, giving rise to the substitution of threonine for methionine at position 136. RNase mapping analysis confirmed this mutation in WR2 and revealed that six other Japanese-type homozygotes carry the same mutation on at least one allele. The remaining Japanese subject, who does not express the Japanese-type phenotype, did not demonstrate this mutation. Southern blot analysis showed that all seven Japanese-type subjects were confined to one TaqI restriction fragment length polymorphism (RFLP) haplotype. These studies provide direct evidence for the nature of the mutation in the Japanese-type APRT deficiency.
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PMID:Human adenine phosphoribosyltransferase deficiency. Demonstration of a single mutant allele common to the Japanese. 334 50

This study reports the first demonstration of specific mutations leading to human adenine phosphoribosyltransferase (APRT) deficiency. The molecular basis of the deficiency was investigated by determining the sequence of both alleles of a patient with a complete deficiency in APRT activity. A trinucleotide deletion, corresponding to phenylalanine on the deduced amino acid sequence, was confirmed on one allele. A single nucleotide insertion, immediately adjacent to the splice site at the 5' end of the fourth intervening sequence, was confirmed on the other allele. This insertion lead to aberrant splicing, as was demonstrated by the absence of exon 4 in the complementary DNA sequence and by altered RNase mapping analysis of the abnormal messenger RNA.
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PMID:Human adenine phosphoribosyltransferase. Identification of allelic mutations at the nucleotide level as a cause of complete deficiency of the enzyme. 368 May 3

Transcriptional regulation of the Chinese hamster ovary (CHO) adenine phosphoribosyltransferase-encoding gene (APRT) was studied. The 5' region of the CHO APRT is G + C-rich, but lacking TATA or CCAAT boxes. RNase protection assays indicate that it contains multiple transcription start points (tsp). A tsp 64 bp upstream from the translation start codon is denoted as +1. Linker-scanning (LS) mutation analysis indicates that the -33 to +19 region is important in regulating APRT transcription. Mutations in the -23 to -14 region abolish transcription initiated from the -23 downstream region. An unidentified protein complex binds to this region. Three Sp1-binding sites are found in the APRT promoter; however, mutations of the Sp1-binding sites do not reduce APRT transcription. Mutations at two putative GCF-binding sites increase levels of transcription.
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PMID:Identification of the cis-elements required for transcriptional control of the Chinese hamster ovary APRT gene. 762 45

The effect of long-term phosphate (Pi) starvation of up to 3 weeks on the levels of purine nucleotides and related compounds was examined using suspension-cultured Catharanthus roseus cells. Levels of adenine and guanine nucleotides, especially ATP and GTP, were markedly reduced during Pi-starvation. There was an increase in the activity of RNase, DNase, 5'- and 3'-nucleotidases and acid phosphatase, which may participate in the hydrolysis of nucleic acids and nucleotides. Accumulation of adenosine, adenine, guanosine and guanine was observed during the long-term Pi starvation. Long-term Pi starvation markedly depressed the flux of transport of exogenously supplied [8-(14)C]adenosine and [8-(14)C]adenine, but these labelled compounds which were taken up by the cells were readily converted to adenine nucleotides even in Pi-starved cells, in which RNA synthesis from these precursors was significantly reduced. The activities of adenosine kinase, adenine phosphoribosyltransferase and adenosine nucleosidase were maintained at a high level in long-term Pi starved cells.
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PMID:Effect of long-term phosphate starvation on the levels and metabolism of purine nucleotides in suspension-cultured Catharanthus roseus cells. 1632 9