Glutamate dehydrogenase coenzyme specificity

There are at least three types of glutamate dehydrogenases which differ in coenzyme specificity those specific for either NAD or NADP and those that can function with both. For brevity, the first two will be abbre-... 

The same 2-BDB-TeA 2, 5 -DP was also found to inactivate the NADP -specific glutamate dehydrogenase from Salmonella typhimurium. The rate of inactivation exhibited a nonlinear dependence on the reagent concentration, indicative of reversible binding prior to irreversible modification (J9). The presence of NADPH or NADP in the reaction mixture completely prevented inactivation, suggesting that 2-BDB-TcA 2, 5 -DP also functioned as an affinity label of the coenzyme site in this NADP -specific dehydrogenase. 

We have emphasized the specific character of macromolecules. Even in the arsenal of enzymes common to all cells we find indications of this specificity. The glucose dehydrogenase of vertebrate liver for example, is not inhibited by toluene, whilst that of E. colt is inhibited. Yeast alcohol dehydrogenase is completely inhibited by O-OOIM iodoacetate, whilst even at a concentration of O-OIM, animal alcohol dehydrogenase remains imaffected. Glutamic add dehydrogenase of yeast requires TPN as a coenzyme whilst the same enzyme from plants needs DPN. 

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