a (2R,3S)-2-alkyl-3-hydroxyalkanoate + NADP(+) => an (R)-2-alkyl-3-oxoalkanoate + NADPH + H(+)
a (2r,3s)-2-alkyl-3-hydroxyalkanoate + nadp(+) => an (r)-2-alkyl-3-oxoalkanoate + nadph + h(+)
a (2R,3S)-2-alkyl-3-hydroxyalkanoate + NADP(+) => an (R)-2-alkyl-3-oxoalkanoate + NADPH + H(+)
a (2r,3s)-2-alkyl-3-hydroxyalkanoate + nadp(+) => an (r)-2-alkyl-3-oxoalkanoate + nadph + h(+)