A new reaction of glutamate dehydrogenase: The enzyme-catalyzed formation of trinitrobenzene from TNBS in the presence of reduced coenzyme

Glutamate dehydrogenase is shown to catalyze the reaction of trinitrobenzene sulfonate with DPNH or TPNH to yield trinitrobenzene, sulfite, and DPN or TPN. The reaction is stereospecific with respect to removal of deuterium from the reduced coenzyme and is affected by the same purine nucleotides which affect the normal activity. In addition, the reaction is inhibited by α-ketoglutarate. No chemical modification of amino acid residues occurs during the catalysis. It is concluded that the TNBS reaction occurs at the catalytic site of the enzyme.