A PSEUDOMONAS SP ALCOHOL-DEHYDROGENASE WITH BROAD SUBSTRATE-SPECIFICITY AND UNUSUAL STEREOSPECIFICITY FOR ORGANIC-SYNTHESIS

A new alcohol dehydrogenase from Pseudomonas sp. strain PED has been isolated and characterized. The enzyme exhibits a broad substrate specificity, accepting aromatic, cyclic, and aliphatic compounds as substrates. The K(m) values were determined as 525-mu-M for NAD and 75-mu-M for 2-propanol with a specific activity of 36 U/mg. The kinetic mechanism is ordered bi-bi with the cofactor binding first and releasing last. The enzyme transfers the pro-R hydride of NADH to the si face of carbonyl compounds to yield (R) alcohols. Synthetic-scale reductions of a number of representative compounds were carried out in high enantiomeric excess with in situ regeneration of NADH using 2-propanol as the hydride source and the same enzyme as catalyst.