Enantioselective oxidation of amphetamine by copper-containing quinoprotein amine oxidases from Escherichia coli and Klebsiella oxytoca

The enantioselective properties of copper-containing quinoprotein amine oxi dase (EC 1.4.3.6) from Escherichia coli K12 and Klebsiella oxytoca in the k inetic resolution of (R,S)-1-phenyl-2-aminopropane, amphetamine, have been determined. Determination of the enantiomeric ratio, E = (k(cat)/K-M)(R)/(k (cat)/K-M)(S), the ratio of specificity constants for the enantiomeric subs trates, can be accomplished in several ways. For practical reasons, we calc ulated E using non-linear regression analysis of initial rate data obtained at a fixed overall concentration of amphetamine mixtures of chiral composi tion ranging from 0 to 50% (R)-(-)-amphetamine [Jongejan et al., Reel. Trav . Chim. Pays-Bas 110 (1990) 247]. It is found that both enzymes catalyze th e enantioselective oxidation of amphetamine with E-values of sufficient mag nitude (E approximate to 15) which may open the possibility for future appl ication of amine oxidase-catalyzed kinetic resolutions of racemic amphetami ne. The preference for the (R)-enantiomer of amphetamine is in agreement wi th the pro-S specificity that has been observed for the conversion of 2-phe nylethylamine. Rationalization of this observation, based on the structure of the E. coli amine oxidase, is discussed. (C) 2000 Elsevier Science B.V. All rights reserved.