The substrate specificity of the heat-stable stereospecific amidase from Klebsiella oxytoca

The substrate specificity of the heat-stable stereospecific amidase from Klebsiella oxytoca was investigated. In addition to the original substrate, 3,3,3-trifluoro-2-hydroxy-2-methylpropanamide, the amidase accepted 2-hydroxy-2-(trifluoromethyl)-butanamide and 3,3,3-trifluoro-2-amino-2-methylpropanamide as substrates. Compounds with larger side chains and compounds where the hydroxyl group was substituted with a methoxy group, or in which the CF3 group was substituted by CCl3, were not accepted. The biotransformation is a new synthetic route to (R)-(+)-3,3,3-trifluoro-2-amino-2-methylpropanoic acid, and its related (S)-(−)-amide, and to (R)-(+)-2-hydroxy-2-(trifluoromethyl)-butanoic acid and its related (S)-(−)-amide.