Escherichia coli glutamine synthesis

The thousands of enzyme-catalyzed chemical reactions in living cells are organized into a series of biochemical (or metabolic) pathways. Each pathway consists of a sequence of catalytic steps. The product of the first reaction becomes the substrate of the next and so on. The number of reactions varies from one pathway to another. For example, animals form glutamine from a-ketoglutarate in a pathway that has two sequential steps, whereas the synthesis of tryptophan by Escherichia coli requires 13 steps. Frequently, biochemical pathways have branch points. For example, chorismate, a metabolic intermediate in tryptophan biosynthesis, is also a precursor of phenylalanine and tyrosine. 

Feng, J., Atkinson, M.R., McGleary, W, Stock, J.B., Wanner, B.L. and Nrnfa, A.J. (1992). Role of phosphorylated metabolic intermediates in the regulation of glutamine synthetase synthesis in Escherichia coli. J. Bacteriol. 174, 6061-6070. 

Carbamoyl phosphate synthesis from ammonia represents one of the prominent activities in ureotelic livers [78]. The enzyme requires N-acetylglutamate and is distinct from the enzyme responsible for carbamoyl phosphate synthesis in extrahepatic tissues and in the livers of uricotelic animals. This second enzyme utilizes glutamine [79], rather than ammonia as the primary nitrogen donor and is found in mushrooms, Escherichia coli, yeast, Ehrlich ascites tumour and several other animal tissues [80]. This enzyme is carbamoyl phosphate synthetase II (ATP carbamate phosphotransferase, EC 2.7.2.2) and catalyses the following reaction ... 

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