Nitric oxide dioxygenase: an enzymic function for flavohemoglobin.
Article Details
- CitationCopy to clipboard
Gardner PR, Gardner AM, Martin LA, Salzman AL
Nitric oxide dioxygenase: an enzymic function for flavohemoglobin.
Proc Natl Acad Sci U S A. 1998 Sep 1;95(18):10378-83.
- PubMed ID
- 9724711 [ View in PubMed]
- Abstract
Nitric oxide (NO*) is a toxin, and various life forms appear to have evolved strategies for its detoxification. NO*-resistant mutants of Escherichia coli were isolated that rapidly consumed NO*. An NO*-converting activity was reconstituted in extracts that required NADPH, FAD, and O2, was cyanide-sensitive, and produced NO3-. This nitric oxide dioxygenase (NOD) contained 19 of 20 N-terminal amino acids identical to those of the E. coli flavohemoglobin. Furthermore, NOD activity was produced by the flavohemoglobin gene and was inducible by NO*. Flavohemoglobin/NOD-deficient mutants were also sensitive to growth inhibition by gaseous NO*. The results identify a function for the evolutionarily conserved flavohemoglobins and, moreover, suggest that NO* detoxification may be a more ancient function for the widely distributed hemoglobins, and associated methemoglobin reductases, than dioxygen transport and storage.