Metabolic Modeling Tutorial
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Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
BioCyc websites down
12/28 - 12/31
for maintenance.
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
BioCyc websites down
12/28 - 12/31
for maintenance.
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
BioCyc websites down
12/28 - 12/31
for maintenance.
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
BioCyc websites down
12/28 - 12/31
for maintenance.
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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:
purine nucleoside phosphorylase Inferred from experiment : deoD ( Escherichia coli K-12 substr. MG1655 )
purine nucleoside phosphorylase Traceable author statement to experimental support : PNP ( Homo sapiens )

In Pathway: purine deoxyribonucleosides degradation I , purine deoxyribonucleosides 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 direction in which it was curated.

Mass balance status: Balanced.

Direct generic reaction:
a purine 2'-deoxyribonucleoside + phosphate = a purine base + 2-deoxy-α-D-ribose 1-phosphate (2.4.2.1)

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): -7.9499817 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: [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:R01969 , Rhea:27738

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

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

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 Sun Dec 21, 2014, biocyc14.