Accepted name: 5-nitrosalicylate dioxygenase
Reaction: 5-nitrosalicylate + O2 = 2-oxo-3-(5-oxofuran-2-ylidene)propanoate + nitrite (overall reaction)
(1a) 5-nitrosalicylate + O2 = 4-nitro-6-oxohepta-2,4-dienedioate
(1b) 4-nitro-6-oxohepta-2,4-dienedioate = 2-oxo-3-(5-oxofuran-2-ylidene)propanoate + nitrite (spontaneous)
Other name(s): naaB (gene name); 5-nitrosalicylate:oxygen 1,2-oxidoreductase (decyclizing)
Systematic name: 5-nitrosalicylate:oxygen 1,2-oxidoreductase (ring-opening)
Comments: The enzyme, characterized from the soil bacterium Bradyrhizobium sp. JS329, is involved in the pathway of 5-nitroanthranilate degradation. It is unusual in being able to catalyse the ring fission without the requirement for prior removal of the nitro group. The product undergoes spontaneous lactonization, with concurrent elimination of the nitro group.
1.  Qu, Y. and Spain, J.C. Biodegradation of 5-nitroanthranilic acid by Bradyrhizobium sp. strain JS329. Appl. Environ. Microbiol. 76 (2010) 1417–1422. [PMID: 20081004]
2.  Qu, Y. and Spain, J.C. Molecular and biochemical characterization of the 5-nitroanthranilic acid degradation pathway in Bradyrhizobium sp. strain JS329. J. Bacteriol. 193 (2011) 3057–3063. [PMID: 21498645]
[EC created 2012]