Nitrogen excess

Let us first consider the situation under conditions of nitrogen excess (see fig. 21.5). The first regulatory protein in the cascade is converted into a uridylyl-removing enzyme. This enzyme hydrolyzes UMP from a PII 3 UMP protein that acts in concert with adenylyltransferase to form adenylate glutamine synthase. The resulting adenylylated enzyme is inactive. 

Fenn, M. E., Poth, M. A., Aber, J. D. et al. (1997). Nitrogen excess in North American Ecosystems predisposing factors, ecosystem responses, and management strategies. Ecological Applications, 8, 706-33. 

Reduced nitrogen. Excess NH3 precipitates Pa hydrous oxide even from 5-M HF. Aqueous Np gives a green hydroxide at pHs near 7, becoming grayish and less soluble on aging. 

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