Influence of Growth Rate on the Enzymes of Ammonia Assimilation in Some Members of the Genus Erwinia

Abstract

~ ~~~~~The influence of specific growth rate on the ammonia-assimilating enzymes glutamine synthetase, NADP-linked glutamate synthase and NADP-linked glutamate dehydrogenase was studied in ammonia-limited and glucose-limited chemostat cultures of Erwinia carotovora var. carotovora, E. nigrijluens and E. amylovora. The response of these organisms, representatives of various ' enzyme groups' within the genus Erwinia, showed considerable variation and confirmed the heterogeneity of the genus with respect to ammonia-assimilating enzymes. The overall significance of the glutamine synthetase/glutamate synthase pathway in any organism where the synthesis of these enzymes is not constitutive is questioned.