Subsystem: Ammonia assimilation
This subsystem's description is:
Ammonium is the preferred nitrogen source for the enteric bacteria. In the presence of ammonium, there is a strong repression of many systems that allow the cells to use alternative nitrogen sources, such as amino acids, inorganic compounds, and urea.
Ammonia can be fixed onto the carbon skeleton of alpha -ketoglutarate to form glutamate by two different pathways in the enteric bacteria. It can be fixed directly onto alpha -ketoglutarate in an NADPH-dependent reaction by glutamate dehydrogenase (GDH). It can also be fixed indirectly by first being attached to glutamate to form glutamine by an ATP-dependent glutamine synthetase (GS), followed by the transfer of the amide nitrogen onto alpha -ketoglutarate by an NADPH-dependent glutamate synthase, also called glutamate-oxoglutarate amidotransferase (GOGAT). No other pathway allows significant net assimilation of ammonia into glutamate.
1 - E. coli / bacteria like: contains adenylyltransferase and NADPH dependent GOGAT
2 - Cyanobacteria-like: no adenylyltransferase, has Ferrodoxin-dependent GOGAT. May also have other GOGATs
3 - Higher-plant like: has NADH dependent GOGAT;
4 - contains adenylyltransferase and 3 ddifferent GOGATs.
For more information, please check out the description and the additional notes tabs, below
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