Characterization of an aldehyde oxidoreductase from Desulfovibrio aminophilus

A. THAPPER; M. G. RIVAS; C. D. BRONDINO; G. FAUQUE; I. MOURA; J. J. G. MOURA

JOURNAL OF INORGANIC BIOCHEMISTRY

Elsevier Science INC

Año: 2006 vol. 100 p. 44 - 50

0162-0134

Aldehyde oxidoreductase (AOR) activity has been found in a number of sulfate-reducing bacteria. The enzyme that is responsible for the conversion of aldehydes to carboxylic acids is a mononuclear molybdenum enzyme belonging to the xanthine oxidase family. We report here the purification and characterization of AOR isolated from the sulfate-reducing bacterium Desulfovibrio (D.) aminophilus DSM 12254, an aminolytic strain performing thiosulfate dismutation. The enzyme is a homodimer (ca. 200 kDa), containing a molybdenumcentre and two [2Fe–2S] clusters per monomer. UV/Visible and electron paramagnetic resonance (EPR) spectra of D. aminophilus AOR recorded in as-prepared and reduced states are similar to those obtained in AORs from Desulfovibrio gigas, Desulfovibrio desulfuricansand Desulfovibrio alaskensis. Despite AOR from D. aminophilus is closely related to other AORs, it presents lower activity towards aldehydes and no activity towards N-heterocyclic compounds, which suggests another possible role for this enzyme in vivo. A comparison of the molecular and EPR properties of AORs from different Desulfovibrio species is also included.