Results 231 to 240 of about 24,465 (266)

Computer Simulations Reveal Substrate Specificity of Glycosidic Bond Cleavage in Native and Mutant Human Purine Nucleoside Phosphorylase.

Biochemistry, 2016
Purine nucleoside phosphorylase (PNP) catalyzes the reversible phosphorolysis of purine ribonucleosides and 2'-deoxyribonucleosides, yielding the purine base and (2'-deoxy)ribose 1-phosphate as products.
G. Isaksen, K. H. Hopmann, J. Åqvist, B. Brandsdal   +3 more
semanticscholar   +1 more source

Purine nucleoside phosphorylase from bovine liver

Comparative Biochemistry and Physiology Part B: Comparative Biochemistry, 1978
1. Purine nucleoside phosphorylase (purine nucleoside:orthophosphate ribosyltransferase, E.C. 2.4.2.1) from liver of cattle, Bos taurus, was purified to homogeneity. Some properties of the enzymes from three different bovine tissues were compared and discussed. 2.
Takeshi Nishino, Zenro Ikezawa, Koji Murakami, Keizo Tsushima   +3 more
openaire   +3 more sources

16 Purine Nucleoside Phosphorylase

1972
Publisher 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
openaire   +2 more sources

Purine Nucleoside Phosphorylase. 2. Catalytic Mechanism

Biochemistry, 1997
X-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, Steven E. Ealick, Mark D. Erion, Johanna D. Stoeckler, Wayne C. Guida   +4 more
openaire   +3 more sources

A new isotopic assay for purine nucleoside phosphorylase

Analytical Biochemistry, 1989
We 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, L. Lee Bennett, R. W. Brockman   +2 more
openaire   +3 more sources

Recognition of Artificial Nucleobases by E. coli Purine Nucleoside Phosphorylase versus its Ser90Ala Mutant in the Synthesis of Base-Modified Nucleosides.

Chemistry, 2015
A wide range of natural purine analogues was used as probe to assess the mechanism of recognition by the wild-type (WT) E. coli purine nucleoside phosphorylase (PNP) versus its Ser90Ala mutant.
I. Fateev, Maria I. Kharitonova, K. Antonov, I. Konstantinova, V. Stepanenko, R. Esipov, F. Seela, Kartik W Temburnikar, K. Seley‐Radtke, V. Stepchenko, Yu. A. Sokolov, A. Miroshnikov, I. Mikhailopulo   +12 more
semanticscholar   +1 more source

A new ultramicrochemical assay for purine nucleoside phosphorylase

Analytical Biochemistry, 1978
Abstract 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, P. Hösli, T. L. Oei, Claude Griscelli, M.P. Uitendaal   +4 more
openaire   +3 more sources

Purine Nucleoside Phosphorylase

1985
It 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
openaire   +2 more sources

A new colorimetric assay for purine nucleoside phosphorylase

Clinical Biochemistry, 1989
A 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
openaire   +3 more sources

Plasma purine nucleoside phosphorylase in cancer patients

Clinica Chimica Acta, 2004
Purine nucleoside phosphorylase (PNP) is the purine salvage enzyme that converts guanosine to guanine and inosine to hypoxanthine.279 samples from patients with differing cancers were collected during treatment at both pre- and post-dose stages for plasma PNP activity and compared with a normal population.Normal plasma PNP activity was found to be 3.2+/
Russell P. Newton, Elton L.L. Roberts, Alan T. Axford   +2 more
openaire   +3 more sources