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discounted EARLY registration ends Dec 31, 2014
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
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MetaCyc Reaction: 2.4.2.1

Superclasses: Reactions Classified By Conversion Type Simple Reactions Chemical Reactions
Reactions Classified By Substrate Small-Molecule Reactions

EC Number: 2.4.2.1

Enzymes and Genes:
xanthosine phosphorylase Inferred from experiment : xapA ( Escherichia coli K-12 substr. MG1655 )
purine nucleoside phosphorylase Inferred from experiment : PNP ( Homo sapiens )
purine nucleoside phosphorylase ( Glycine max )

In Pathway: xanthine and xanthosine salvage , urate biosynthesis/inosine 5'-phosphate degradation , purine ribonucleosides degradation

Note that this reaction equation differs from the official Enzyme Commission reaction equations for this EC number, which can be found here and here .

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

Mass balance status: Balanced.

Enzyme Commission Primary Name: purine-nucleoside phosphorylase

Enzyme Commission Synonyms: inosine phosphorylase, PNPase, PUNPI, PUNPII, inosine-guanosine phosphorylase, nucleotide phosphatase, purine deoxynucleoside phosphorylase, purine deoxyribonucleoside phosphorylase, purine nucleoside phosphorylase, purine ribonucleoside phosphorylase

Standard Gibbs Free Energy (ΔrG in kcal/mol): 0.72998047 Inferred by computational analysis [Latendresse13]

Enzyme Commission Summary:
Specificity not completely determined. Can also catalyse ribosyltransferase reactions of the type catalysed by EC 2.4.2.5, nucleoside ribosyltransferase.

Citations: [Bzowska00, Stoychev02, Agarwal69, Heppel52, Saunders69, Tsuboi57, Friedkin61, Kalckar47]

Gene-Reaction Schematic: ?

Instance reactions of [a purine ribonucleoside + phosphate ↔ a purine base + α-D-ribose-1-phosphate] (2.4.2.1):
i1: adenosine + phosphate ↔ adenine + α-D-ribose-1-phosphate (2.4.2.1)

i2: guanosine + phosphate ↔ guanine + α-D-ribose-1-phosphate (2.4.2.1/2.4.2.15)

i3: inosine + phosphate ↔ hypoxanthine + α-D-ribose-1-phosphate (2.4.2.1)

Unification Links: KEGG:R02297 , Rhea:27638

Relationship Links: BRENDA:EC:2.4.2.1 , ENZYME:EC:2.4.2.1 , IUBMB-ExplorEnz:EC:2.4.2.1


References

Agarwal69: Agarwal RP, Parks RE (1969). "Purine nucleoside phosphorylase from human erythrocytes. IV. Crystallization and some properties." J Biol Chem 244(4);644-7. PMID: 5768862

Bzowska00: Bzowska A, Kulikowska E, Shugar D (2000). "Purine nucleoside phosphorylases: properties, functions, and clinical aspects." Pharmacol Ther 88(3);349-425. PMID: 11337031

Friedkin61: Friedkin M, Kalckar H (1961). "Nucleoside phosphorylases." In: Boyer, P.D., Lardy, H. and Myrbäck, K. (Eds), The Enzymes, 2nd edn, vol. 5, Academic Press, New York, pp. 237-255.

Heppel52: Heppel LA, Hilmoe RJ (1952). "[Phosphorolysis and hydrolysis of purine ribosides by enzymes from yeast]." J Biol Chem 198(2);683-94. PMID: 12999785

Kalckar47: Kalckar HM (1947). "The enzymatic synthesis of purine ribosides." J. Biol. Chem. 167 477-486.

Latendresse13: Latendresse M. (2013). "Computing Gibbs Free Energy of Compounds and Reactions in MetaCyc."

Saunders69: Saunders PP, Wilson BA, Saunders GF (1969). "Purification and comparative properties of a pyrimidine nucleoside phosphorylase from Bacillus stearothermophilus." J Biol Chem 244(13);3691-7. PMID: 4978445

Stoychev02: Stoychev G, Kierdaszuk B, Shugar D (2002). "Xanthosine and xanthine. Substrate properties with purine nucleoside phosphorylases, and relevance to other enzyme systems." Eur J Biochem 269(16);4048-57. PMID: 12180982

Tsuboi57: Tsuboi KK, Hudson PB (1957). "Enzymes of the human erythrocyte. I. Purine nucleoside phosphorylase; isolation procedure." J Biol Chem 224(2);879-87. PMID: 13405917


Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 18.5 on Fri Dec 19, 2014, biocyc12.