Purification and characterization of an alcohol dehydrogenase from 1,2-propanediol-grown Desulfovibrio strain HDv

Abstract

The sulfate-reducing bacterimDesulfovibrio strain HDv (DSM 6830) grew faster on (S)- and on (R, S)-1,2-propanediol (μmax 0.053 h−) than on (R)-propanediol (0.017 h−1) and ethanol (0.027 h−1). From (R, S)-1,2-propanediol-grown cells, an alcohol dehydrogenase was purified. The enzyme was oxygen-labile, NAD-dependent, and decameric; the subunit mol. mass was 48 kDa. The N-terminal amino acid sequence indicated similarity to alcohol dehydrogenases belonging to family III of NAD-dependent alcohol dehydrogenases, the first 21 N-terminal amino acids being identical to those of theDesulfovibrio gigas alcohol dehydrogenase. Best substrates were ethanol and propanol (K m of 0.48 and 0.33 mM, respectively). (R, S)-1,2-Propanediol was a relatively poor substrate for the enzyme, but activities in cell extracts were high enough to account for the growth rate. The enzyme showed a preference for (S)-1,2-propanediol over (R)-1,2-propanediol. Antibodies raised against the alcohol dehydrogenase ofD. gigas showed cross-reactivity with the alcohol dehydrogenase ofDesulfovibrio strain HDv and with cell extracts of six other ethanol-grown sulfate-reducing bacteria.