Zusammenfassung
A Comamonas acidovorans strain, designated NBA-10, was isolated on
4-nitrobenzoate as sole carbon and energy source. When grown on
4-nitrobenzoate, it was simultaneously adapted to 4-nitrosobenzoate
and 4-hydroxylaminobenzoate but not to 4-hydroxybenzoate or 4-aminobenzoate.
In cell extracts with NADPH present, 4-nitrobenzoate was degraded
to 4-hydroxylaminobenzoate and 3,4-dihydroxybenzoate. Partial purification
of the 4-nitrobenzoate reductase revealed that 4-nitrobenzoate is
degraded via 4-nitrosobenzoate to 4-hydroxylamino-benzoate. The
substrate specificity of the enzyme was narrow and NADPH was 15
times more effective as a cofactor than NADH. The results provide
evidence for a novel pathway for aerobic degradation of 4-nitrobenzoate,
since neither 4-hydroxybenzoate nor 4-aminobenzoate were involved
in the degradative pathway.
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