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)

The adenine phosphoribosyltransferase (AMP: pyrophosphate phosphoribosyltransferase, EC 2.4.2.7) of rat liver was purified to a specific activity of 1.1 mumol of AMP formed per min per mg. The enzyme activity is associated with an apparently homogenous protein as shown by isoelectrofocusing, acrylamide gel electrophoresis, and N-terminal amino acids analysis (phenylalanine). The molecular weight of the enzyme was estimated to be approx. 20 000 by acrylamide gel electrophoresis in the presence of sodium dodecylsulfate and by sucrose density gradient zone sedimentation. The rat liver enzyme exhibited initial burst synthesis of AMP when 1-pyrophosphorylribose 5-phosphate was added. The 1-pyrophosphorylribose 5-phosphate initial-burst activity copurifies with the adenine phosphoribosyltransferase activity. A PH optimum of 10.0 was demonstrable for the adenine phosphoribosyltransferase. The initial-burst and steady-state phases of AMP synthesis catalyzed by highly purified rat liver adenine phosphoribosyltransferase have been partially characterized by the use of ligands which bind to sulfhydryl groups. Studies utilizing p-chloromercuribenzoate and HgCl2 as inhibitors of AMP sulfhydryl during the initial-burst and steady-state phases have revealed that sulfhydryl groups with different rates of ligand binding are present in the enzyme. The initial-burst phase was thereby delineated from the steady-state phase by use of these mercurial ligands. This delineation was also accomplished by titration with the Mg-2+ chelator, EDTA. The inhibitory effects of mercurials and EDTA were reversed by beta-mercaptoethanol and excess Mg-2+, respectively. Quantitative binding studies with 5,5'-dithiobis(2-nitrobenzoic acid) and p-chloromercuribenzoate yielded values of 3.65 and 3.6 mol of sulfhydryl per mol of enzyme, respectively. 3.3 mol of cysteic acid per mol of performic acid-oxidized enzyme were found by amino acid analysis.
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PMID:Purification and properties of rat liver adenine phosphoribosyltransferase. 23 79

Somatic cell hybridization techniques were applied to gene linkage analysis in the laboratory mouse. Cells of an established line of Chinese hamster lung fibroblasts were fused with mouse embryo fibroblasts and with mouse peritoneal macrophages obtained from different inbred strains. From 3 hybridization experiments, 123 primary and secondary clones were isolated in HAT selective medium and 24 were back-selected in 8-azaguanine. Hybrid clones were characterized for the expression of 16 murine isozymes by starch, acrylamide, and Cellogel electrophoresis, and on the basis of segregation data, 3 syntenic associations could be made. Malate oxidoreductase decarboxylating (MOD) and mannose phosphate isomerase (MPI) segregated concordantly, confirming an established linkage relationship; adenine phosphoribosyltransferase (APRT) segregated concordantly with glutathione reductase (GR) which is known to be on chromosome 8; alpha-galactosidase was observed to be syntenic with hypoxanthine phosphoribosyltransferase (HPRT), and X-linked enzyme. All other isozymes examined segregated independently of one another.
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PMID:Gene linkage analysis in the mouse by somatic cell hybridization: assignment of adenine phosphoribosyltransferase to chromosome 8 and alpha-galactosidase to the X chromosome. 123 12