EVIDENCE FOR NADH-LINKED AND NADPH-LINKED GLUTAMATE-DEHYDROGENASES IN TRYPANOSOMA-CRUZI EPIMASTIGOTES

SYNOPSIS Two glutamate dehydrogenases, NADH‐linked (EC 1.2.1.2) and NADPH‐linked (EC 1.2.1.4.) were isolated from the epimastigote forms of Trypanosoma cruzi and purified. Both enzymes exist as hexamers. The molecular weights of the native NADH‐and NADPH‐linked glutamate dehydrogenases were estimated to be 360,000 and 265,000, respectively, and those of the subunits to be 58,000 and 43,000, respectively. The isoelectric point of the NADH‐linked dehydrogenase is at pH 5.25 and that of the NADPH‐linked enzyme at pH 5.1. The activities of both enzymes are regulated by product inhibition. In addition, purine nucleotides were shown to be potent inhibitors of the NADH‐linked glutamate dehydrogenase. Copyright © 1979, Wiley Blackwell. All rights reserved