Inactivation of glutamate decarboxylase by bromopyruvate

Bromopyruvate was shown to inhibit $\text{E. coli}$ glutamate decarboxylase competitively with respect to L-glutamate. High concentrations of bromopyruvate caused a time-dependent inactivation of glutamate decarboxylase. However, the apoenzyme was rapidly and irreversibly inactivated by bromopyruvate with an inactivation constant of 490 1 mole^?1 min^?1 at pH 5.7. Studies with labeled bromopyruvate indicated that approximately 1.7 moles of inhibitor were bound per subunit of apoenzyme.