IUBMB Enzyme Nomenclature


Accepted name: protein N-terminal glutamine amidohydrolase

Reaction: N-terminal L-glutaminyl-[protein] + H2O = N-terminal L-glutamyl-[protein] + NH3

Other name(s): NTAQ1 (gene name)

Systematic name: protein N-terminal glutamine amidohydrolase

Comments: This enzyme participates in the eukaryotic ubiquitin-dependent Arg/N-end rule pathway of protein degradation, promoting the turnover of intracellular proteins that initiate with Met-Gln. Following the acetylation and removal of the initiator methionine, the exposed N-terminal glutamine is deaminated, resulting in its conversion to L-glutamate. The latter serves as a substrate for EC, arginyltransferase, making the protein susceptible to arginylation, polyubiquitination and degradation as specified by the N-end rule.

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


1. Wang, H., Piatkov, K.I., Brower, C.S. and Varshavsky, A. Glutamine-specific N-terminal amidase, a component of the N-end rule pathway. Mol. Cell 34 (2009) 686-695. [PMID: 19560421]

[EC created 2016]

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