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16 Purine Nucleoside Phosphorylase
1972Publisher Summary This chapter focuses on purine nucleoside phosphorylases (PNPases), which are widely distributed in nature and have been identified and studied in a number of tissues in mammals, chickens, fish, yeast, and in several species of bacteria. In the erythrocytes of dogs, the activity of PNPase is remarkably low when compared with the red
R.E. Parks, R.P. Agarwal
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Purine Nucleoside Phosphorylase. 2. Catalytic Mechanism
Biochemistry, 1997X-ray crystallography, molecular modeling, and site-directed mutagenesis were used to delineate the catalytic mechanism of purine nucleoside phosphorylase (PNP). PNP catalyzes the reversible phosphorolysis of purine nucleosides to the corresponding purine base and ribose 1-phosphate using a substrate-assisted catalytic mechanism.
Richard L. Walter +4 more
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A new colorimetric assay for purine nucleoside phosphorylase
Clinical Biochemistry, 1989A new colorimetric procedure for the determination of purine nucleoside phosphorylase (PNP, E.C. 2.4.2.1) activity is described. In this procedure, the hydrogen peroxide formed in the PNP-xanthine oxidase reaction is used to oxidize the chromogenic reagents--3,5-dichloro-2-hydroxybenzenesulfonic acid/4-aminophenazone using the enzyme peroxidase.
Peter Cashion, Samuel Y. Chu, Min Jiang
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Purine Nucleoside Phosphorylase
1985It has long been appreciated that purine nucleoside phosphorylase (PNP; purine nucleoside: orthophosphate ribosyltransferase, EC 2.4.2.1) may play a role in cancer chemotherapy by catalyzing the degradation of potentially cytotoxic purine deoxynucleoside analogs, e.g., 2′-deoxy-6-thioguanosine.
Johanna D. Stoeckler, Robert E. Parks
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A new ultramicrochemical assay for purine nucleoside phosphorylase
Analytical Biochemistry, 1978Abstract An ultramicrochemical method using radioactive substrates has been developed for the quantitation of purine nucleoside phosphorylase (NP) activity in single cells. NP activity can reproducibly be measured in both directions of the enzyme reaction. A quantitative relationship between the number of cells incubated and the NP activity was found.
C. H. M. M. de Bruyn +4 more
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A new isotopic assay for purine nucleoside phosphorylase
Analytical Biochemistry, 1989We have developed a new assay for purine nucleoside phosphorylase which is based on the release of tritium when [2-3H]inosine is used as the substrate and the reaction is coupled with xanthine oxidase. After the reaction is terminated, residual [2-3H]inosine is adsorbed on charcoal and the supernatant solution is assayed for radioactivity by liquid ...
Chi-Hsiung Chang +2 more
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Inhibitors of the enzyme purine nucleoside phosphorylase
Expert Opinion on Therapeutic Patents, 1998The enzyme purine nucleoside phosphorylase (PNP) catalyses the reversible cleavage of purine nucleosides to the purine base and ribose-1-phosphate. Several cases of a rare genetic disorder in which PNP is lacking have been reported in children. These children were found to be T-cell immunodeficient while their B-cell immunity remained normal.
Philip E. Morris, John A. Montgomery
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Purine nucleoside phosphorylase polymorphism in sheep erythrocytes
Biochemical Genetics, 1977A polymorphism of purine nucleoside phosphorylase is described in sheep erythrocytes. Two isozymes were distinguished electrophoretically, one with high activity (NP-1) and one with low activity (NP-2). Breeding data suggest that the two isozymes are the product of two codominant alleles, NP1 and NP2.
P. G. Board, J. E. Smith
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Purine Nucleoside Phosphorylase Deficiency: A Mutation Update
Nucleosides, Nucleotides and Nucleic Acids, 2011Purine nucleoside phosphorylase (PNPase) deficiency is an autosomal recessive disorder affecting purine degradation and salvage pathways. Clinically, patients typically present with severe immunodeficiency, neurological dysfunction, and autoimmunity. Biochemically, PNPase deficiency may be suspected in the presence of hypouricemia.
A. Corrigan +5 more
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