Nitric oxide dioxygenase: An enzymic function for flavohemoglobin
AUTOR(ES)
Gardner, Paul R.
FONTE
The National Academy of Sciences
RESUMO
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.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=27902Documentos Relacionados
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