ENANTIOSELECTIVE OXIDATION OF SECONDARY ALCOHOLS BY QUINOHEMOPROTEIN ALCOHOL-DEHYDROGENASE FROM COMAMONAS-TESTOSTERONI

Purified and reconstituted quinohaemoprotein alcohol dehydrogenase (QH -EDH) from Comamonas testosteroni is shown to oxidize secondary alcoho ls enantioselectively. The products formed during the oxidation of sec ondary alcohols were positively identified as the corresponding ketone s. In the oxidation of chiral secondary n-alkyl alcohols a preference of the enzyme for the S(+)alcohols was found. The apparent kinetic par ameters (K-m and V-max) for a range of n-alkyl alcohols depend on the length of the alcohol chain and the location of the hydroxyl function in the chain. The enzyme is stable up to a temperature of 37 degrees C . Above this temperature the activity is irreversibly lost. The pH opt imum of the enzyme in the conversion of secondary alcohols is 7.7.