Enzyme-activated inhibition of bacterial D-amino acid transaminase by beta-cyano-D-alanine.

beta-Cyano-D-alanine is an efficient suicide substrate (Ki = 10 microM) of D-amino acid transaminase. This apparent inactivation is temperature dependent: it is irreversible at 10 degrees C or below and becomes progressively reversible at higher temperatures. Since at higher temperatures the apparent reactivation process predominates over the inactivation reaction, the reactivation process is considered to be endothermic. The nature of this reversibility suggests the formation of a heat labile bond between the inhibitor molecule and a nucleophilic group on the enzyme.