IUBMB Enzyme Nomenclature

EC 6.3.4.26

Accepted name: guanidine carboxylase

Reaction: ATP + guanidine + hydrogencarbonate = ADP + phosphate + carboxyguanidine

Systematic name: guanidine:carbon-dioxide ligase (ADP-forming)

Comments: A biotinyl-protein. This bacterial enzyme is similar to EC 6.3.4.6, urea carboxylase, yet unlike the fungal enzyme it displays a strong substrate preference for guanidine over urea. In addition, unlike the fungal enzyme, which is bifunctional, the bacterial enzyme is monofunctional. The enzyme participates in a pathway for guanidine degradation to ammonia and CO2.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:

References:

1. Kanamori, T., Kanou, N., Atomi, H. and Imanaka, T. Enzymatic characterization of a prokaryotic urea carboxylase. J. Bacteriol. 186 (2004) 2532-2539. [PMID: 15090492]

2. Nelson, J.W., Atilho, R.M., Sherlock, M.E., Stockbridge, R.B. and Breaker, R.R. Metabolism of free guanidine in bacteria Is regulated by a widespread riboswitch class. Mol. Cell 65 (2017) 220-230. [PMID: 27989440]

3. Schneider, N.O., Tassoulas, L.J., Zeng, D., Laseke, A.J., Reiter, N.J., Wackett, L.P. and Maurice, M.S. Solving the conundrum: widespread proteins annotated for urea metabolism in bacteria are carboxyguanidine deiminases mediating nitrogen assimilation from guanidine. Biochemistry 59 (2020) 3258-3270. [PMID: 32786413]

[EC 6.3.4.26 created 2025]


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