ISSN:
1432-072X
Keywords:
Ammonia assimilation
;
l-Alanine dehydrogenase
;
l-Alanine: 2-oxoglutarate aminotransferase
;
R. capsulata E1F1
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Rhodopseudomonas capsulata E1F1 growing phototrophically in different inorganic nitrogen sources assimilated ammonia through the reactions of the glutamine synthetase/glutamate synthase (GS/GOGAT) pathway. Addition of either methionine sulphoximine (MSX) or azaserine to N2-fixing cells resulted in the cessation of growth, which did not occur when these inhibitors were added to bacteria growing on l-glutamate. In nitrate-assimilating cells MSX or azaserine prevented both growth and nitrate uptake with simultaneous excretion of ammonia to the medium. In addition, MSX inactivated glutamine synthetase but neither glutamate synthase nor nitrate reductase, which, in contrast, were inactivated by azaserine. The excreted ammonia was taken up together with nitrate once growth was resumed, this uptake being coincident with the appearance of an NADPH-linked alanine dehydrogenase aminating activity and a marked increase of alanine: 2-oxoglutarate aminotransferase levels.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00404790
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