2.6.1.54 D-glutamate slight inhibition 2.6.1.54 diisopropyl phosphofluoride 0.3 mM, complete inhibition 2.6.1.54 L-cysteine about 35% inhibition 2.6.1.54 additional information not inhibited by sulfhydryl compounds, e.g. PCMB, phenylmercuric acetate and mercuric chloride 2.6.1.54 pyridoxal 5'-phosphate product inhibition