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

The sulfate-reducing bacterium Desulfovibrio strain HDv (DSM 6830) gre w faster on (S)- and on (R, S)-1,2-propanediol (mu(max) 0.053 h(-1)) t han 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 purifi ed. The enzyme was oxygen-labile, NAD-dependent, and decameric; the su bunit mel. mass was 48 kDa. The N-terminal amino acid sequence indicat ed 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 dehydroge nase. 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 substr ate for the enzyme, but activities in cell extracts were high enough t o account for the growth rate. The enzyme showed a preference for (S)- 1,2-propanediol over (R)-1,2-propanediol. Antibodies raised against th e alcohol dehydrogenase of D. gigas showed cross-reactivity with the a lcohol dehydrogenase of Desulfovibrio strain HDv and with cell extract s of six other ethanol-grown sulfate-reducing bacteria.