PURIFICATION AND CHARACTERIZATION OF AN ALCOHOL-DEHYDROGENASE FROM 1,2-PROPANEDIOL-GROWN DESULFOVIBRIO STRAIN HDV

The sulfate-reducing bacterium Desulfovibrio strain HDv (DSM 6830) grew faster on (S)- and on (R, S)-1,2-propanediol (mu(max) 0.053 h(-1)) 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 mel. 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 the Desulfovibrio 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 of D. gigas showed cross-reactivity with the alcohol dehydrogenase of Desulfovibrio strain HDv and with cell extracts of six other ethanol-grown sulfate-reducing bacteria.