Isolation of a multiheme protein with features of a hydrazine-oxidizing enzyme from an anaerobic ammonium-oxidizing enrichment culture.

ABSTRACT: A multiheme protein having hydrazine-oxidizing activity was purified from enriched culture from a reactor in which an anammox bacterium, strain KSU-1, was dominant. The enzyme has oxidizing activity toward hydrazine but not hydroxylamine and is a 130-kDa homodimer composed of a 62-kDa polypeptide containing eight hemes. It was therefore named hydrazine-oxidizing enzyme (HZO). With cytochrome c as an electron acceptor, the V(max) and K(m) for hydrazine are 6.2 +/- 0.3 micromol/min.mg and 5.5 +/- 0.6 microM, respectively. Hydrazine (25 microM) induced an increase in the proportion of reduced form in the spectrum, whereas hydroxylamine (500 microM) did not. Two genes coding for HZO, hzoA and hzoB, were identified within the metagenomic DNA from the culture. The genes encode the same amino aci

SUBMITTER: Shimamura M 

PROVIDER: S-EPMC1828659 | biostudies-literature | 2007 Feb

REPOSITORIES: biostudies-literature