Characterization and further stabilization of a new anti-prelog specific alcohol dehydrogenase from Thermus thermophilus HB27 for asymmetric reduction of carbonyl compounds.

The use of dehydrogenases in asymmetric chemistry has exponentially grown in the last decades facilitated by the genome mining. Here, a new short-chain alcohol dehydrogenase from Thermus thermophilus HB27 has been expressed, purified, characterized and stabilized by immobilization on solid supports. The enzyme catalyzes both oxidative and reductive reactions at neutral pH with a broad range of substrates. Its highest activity was found towards the reduction of 2,2',2″-trifluoroacetophenone (85 U/mg at 65 °C and pH 7). Moreover, the enzyme was stabilized more than 200-fold by multipoint covalent immobilization on agarose matrixes via glyoxyl chemistry. Such heterogeneous catalyst coupled to an immobilized cofactor recycling partner performed the quantitative asymmetric reduction of 2,2',2″-trifluoroacetophenone and rac-2-phenylpropanal to (S)-(+)-α-(trifluoromethyl)benzyl alcohol and (R)-2-phenyl-1-propanol with enantiomeric excesses of 96% and 71%, respectively. To our knowledge this is the first alcohol dehydrogenase from a thermophilic source with anti-Prelog selectivity for aryl ketones and that preferentially produces R-profens.