MetaCyc Reaction:

Superclasses: Reactions Classified By Conversion TypeSimple ReactionsChemical ReactionsComposite Reactions
Reactions Classified By SubstrateSmall-Molecule Reactions

EC Number:

Enzymes and Genes:

Stenotrophomonas maltophilia: nucleoside oxidaseInferred from experiment

The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the direction in which it was curated.

Most BioCyc compounds have been protonated to a reference pH value of 7.3. Please see the PGDB Concepts Guide for more information.

Mass balance status: Balanced.

Enzyme Commission Primary Name: nucleoside oxidase

2 inosine + oxygen → 2 5'-dehydroinosine + 2 H2O,
2 5'-dehydroinosine + oxygen → 2 9-riburonosylhypoxanthine + 2 H+

Standard Gibbs Free Energy (ΔrG in kcal/mol): -113.9811Inferred by computational analysis [Latendresse13]

Enzyme Commission Summary:
Other purine and pyrimidine nucleosides (as well as 2'-deoxynucleosides) are substrates, but ribose and nucleotides are not substrates.

The overall reaction takes place in two separate steps, with the 5'-dehydro nucleoside being released from the enzyme to serve as substrate for the second reaction.

The two reactions are:

2 inosine + oxygen → 2 5'-dehydroinosine + 2 H2O

2 5'-dehydroinosine + oxygen → 2 9-riburonosylhypoxanthine + 2 H+

This enzyme differs from EC, nucleoside oxidase (H2O2-forming), as it produces water rather than hydrogen peroxide.

Citations: [Isono89a]

Gene-Reaction Schematic

Gene-Reaction Schematic

Unification Links: KEGG:R05821

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

Revised 05-Aug-2009 by Caspi R, SRI International


Isono89a: Isono, Y, Sudo, T., Hoshino, M. (1989). "Purification and reaction of a new enzyme, nucleoside oxidase." Agric. Biol. Chem. 53:1663-1669.

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

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
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