Characterization of the subunits of purine nucleoside phosphorylase from cultured normal human fibroblasts

1979 ◽  
Vol 17 (7-8) ◽  
pp. 621-630 ◽  
Author(s):  
Vassilis I. Zannis ◽  
Lorraine J. Gudas ◽  
David W. Martin
Keyword(s):  
Purine Nucleoside Phosphorylase ◽  
Human Fibroblasts ◽  
Purine Nucleoside ◽  
Nucleoside Phosphorylase ◽  
Normal Human

Overexpression, purification and characterization of functional calf purine nucleoside phosphorylase (PNP)

2008 ◽  
Vol 61 (2) ◽  
pp. 122-130 ◽  
Author(s):  
Katarzyna Breer ◽  
Agnieszka Girstun ◽  
Beata Wielgus-Kutrowska ◽  
Krzysztof Staroń ◽  
Agnieszka Bzowska
Keyword(s):  
Purine Nucleoside Phosphorylase ◽  
Purine Nucleoside ◽  
Purification And Characterization ◽  
Nucleoside Phosphorylase

Purification and characterization of purine nucleoside phosphorylase from developing embryos of Hyalomma dromedarii

1991 ◽  
Vol 69 (4) ◽  
pp. 223-231 ◽  
Author(s):  
Mamdouh Y. Kamel ◽  
Afaf S. Fahmy ◽  
Abdel H. Ghazy ◽  
Magda A. Mohamed
Keyword(s):  
Purine Nucleoside Phosphorylase ◽  
Catalytic Mechanism ◽  
Kinetic Studies ◽  
Purine Nucleoside ◽  
Hyalomma Dromedarii ◽  
Ph Optimum ◽  
Nucleoside Phosphorylase ◽  
Apparent Homogeneity ◽  
Camel Tick

Purine nucleoside phosphorylase from Hyalomma dromedarii, the camel tick, was purified to apparent homogeneity. A molecular weight of 56 000 – 58 000 was estimated for both the native and denatured enzyme, suggesting that the enzyme is monomeric. Unlike purine nucleoside phosphorylase preparations from other tissues, the H. dromedarii enzyme was unstable in the presence of β-mercaptoethanol. The enzyme had a sharp pH optimum at pH 6.5. It catalyzed the phosphorolysis and arsenolysis of ribo- and deoxyribo-nucleosides of hypoxanthine and guanine, but not of adenine or pyrimidine nucleosides. The Km values of the enzyme at the optimal pH for inosine, deoxyinosine, guanosine, and deoxyguanosine were 0.31, 0.67, 0.55, and 0.33 mM, respectively. Inactivation and kinetic studies suggested that histidine and cysteine residues were essential for activity. The pKa values determined for catalytic ionizable groups were 6–7 and 8–9. The enzyme was completely inactivated by thiol reagents and reactivated by excess β-mercaptoethanol. The enzyme was also susceptible to pH-dependent photooxidation in the presence of methylene blue, implicating histidine. Initial velocity studies showed an intersecting pattern of double-reciprocal plots of the data, consistent with a sequential mechanism.Key words: Acarina, Hyalomma dromedarii, purine nucleoside phosphorylase, kinetics, active site, catalytic mechanism.

Expression, Purification, and Characterization of Recombinant Purine Nucleoside Phosphorylase from Escherichia coli

2001 ◽  
Vol 22 (2) ◽  
pp. 180-188 ◽  
Author(s):  
John Lee ◽  
Serena Filosa ◽  
Julie Bonvin ◽  
Sebastien Guyon ◽  
Raphael A. Aponte ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Purine Nucleoside Phosphorylase ◽  
Purine Nucleoside ◽  
Purification And Characterization ◽  
Nucleoside Phosphorylase

scholarly journals Identification and characterization of a novel gene of grouper iridovirus encoding a purine nucleoside phosphorylase

2004 ◽  
Vol 85 (10) ◽  
pp. 2883-2892 ◽  
Author(s):  
Jing-Wen Ting ◽  
Min-Feng Wu ◽  
Chih-Tung Tsai ◽  
Ching-Chun Lin ◽  
Ing-Cherng Guo ◽  
...  
Keyword(s):  
Purine Nucleoside Phosphorylase ◽  
Enzymic Activity ◽  
Host Cells ◽  
Purine Nucleoside ◽  
Nucleoside Phosphorylase ◽  
Egfp Reporter ◽  
Key Enzyme ◽  
Egfp Fusion Protein ◽  
Identification And Characterization

Purine nucleoside phosphorylase (PNP) is a key enzyme in the purine salvage pathway. It catalyses the reversible phosphorolysis of purine (2′-deoxy)ribonucleosides to free bases and (2′-deoxy)ribose 1-phosphates. Here, a novel piscine viral PNP gene that was identified from grouper iridovirus (GIV), a causative agent of an epizootic fish disease, is reported. This putative GIV PNP gene encodes a protein of 285 aa with a predicted molecular mass of 30 332 Da and shows high similarity to the human PNP gene. Northern and Western blot analyses of GIV-infected grouper kidney (GK) cells revealed that PNP expression increased in cells with time from 6 h post-infection. Immunocytochemistry localized GIV PNP in the cytoplasm of GIV-infected host cells. PNP–EGFP fusion protein was also observed in the cytoplasm of PNP–EGFP reporter construct-transfected GK and HeLa cells. From HPLC analysis, the recombinant GIV PNP protein was shown to catalyse the reversible phosphorolysis of purine nucleosides and could accept guanosine, inosine and adenosine as substrates. In conclusion, this is the first report of a viral PNP with enzymic activity.

Sign in / Sign up

Export Citation Format

Share Document