Article révisé par les pairs
Résumé : Mutations which inactivate the NADP-glutamate dehydrogenase (anabolic GDHase) pleiotropically release the ammonia inhibition (NH4+ effect) on a number of distinct catabolic activities. In addition to releasing inhibition on several permeability functions (1), these mutations suppress the NH4+ effect on the synthesis of arginase, urea amidolyase and allantoinase. They do not affect the NH4+ effect on the NAD-glutamate dehydrogenase. Two mechanisms of action of these mutations have to be considered, namely a modification of the process of induction (such as removal of inducer exclusion) and a suppression of nitrogen catabolite repression. © 1973.