Mechanisms and stereochemistry of the activation of (2S)- and (2R)-serine O-sulfate as suicide inhibitors for Escherichia coli glutamic acid decarboxylase

Abstract

E. coli glutamic acid decarboxylase is inactivated by both enantiomers of the suicide inhibitor serine O-sulfate; inactivation by the (2S)-enantiomer involves C^α–H bond cleavage while inactivation by the (2R)-isomer involves C^α-decarboxylation. Both processes occur on the 4′-Re-face of the coenzyme, the opposite face to that utilised in physiological decarboxylation.