The enzyme uridylylates and de-uridylylates the small trimeric protein PII. The enzymes from Escherichia coli and Salmonella typhimurium have been wrongly identified, in some databases, as EC 184.108.40.206 (UDP-glucose—hexose-1-phosphate uridylyltransferase), from which it differs greatly in both reaction catalysed and sequence.
Garcia, E., Rhee, S.G. Cascade control of Escherichia coli glutamate synthetase. Purification and properties of PII uridylyltransferase and uridylyl-removing enzyme. J. Biol. Chem.258 (1983) 2246–2253. [PMID: 6130097]
Van Heeswijk, W., Rabenberg, M., Westerhoff, H., Kahn, D. The genes of the glutamate synthetase adenylylation cascade are not regulated by nitrogen in Escherichia coli. Mol. Microbiol.9 (1993) 443–457. [PMID: 8412694]