Reaction: inosine + O2 = 9-riburonosylhypoxanthine + 2 H2O
(1a) 2 inosine + O2 = 2 5'-dehydroinosine + 2 H2O
(1b) 2 5'-dehydroinosine + O2 = 2 9-riburonosylhypoxanthine
Systematic name: nucleoside:oxygen 5'-oxidoreductase
Comments: Other purine and pyrimidine nucleosides (as well as 2'-deoxyribonucleosides) 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. This enzyme differs from EC 1.1.3.39, nucleoside oxidase (H2O2-forming), as it produces water rather than hydrogen peroxide.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:
References:
1. Isono, Y., Sudo, T. and Hoshino, M. Purification and reaction of a new enzyme, nucleoside oxidase. Agric. Biol. Chem. 53 (1989) 1663-1669.
2. Isono, Y., Sudo, T. and Hoshino, M. Properties of a new enzyme, nucleoside oxidase, from Pseudomonas maltophilia LB-86. Agric. Biol. Chem. 53 (1989) 1671-1677.