Substrate-selective mechanisms in biocatalysis demonstrated with a versatile and efficient aldolase antibody

A structure-activity relationship study with a series of aldol substrates shows that the mechanism of the antibody 38C2-catalyzed retrograde aldol reaction depends on the nature of the substrate With electron-deficient substrates an early deprotonation precedes the C---C bond cleavage while with electron-rich substrates the catalytic mechanism involves an initial C---C bond cleavage leading to a positively charged intermediate.