IUBMB Enzyme Nomenclature


Accepted name: tRNAMet cytidine acetyltransferase

Reaction: [elongator tRNAMet]-cytidine34 + ATP + acetyl-CoA + H2O = CoA + [elongator tRNAMet]-N4-acetylcytidine34 + ADP + phosphate

Other name(s): YpfI; TmcA

Systematic name: acetyl-CoA: [elongator tRNAMet]-cytidine34 N4-acetyltransferase (ATP-hydrolysing)

Comments: The enzyme acetylates the wobble base cytidine34 of the CAU anticodon of elongation-specific tRNAMet. Escherichia coli TmcA strictly discriminates elongator tRNAMet from tRNAIle, which is structurally similar and has the same anticodon loop, mainly by recognizing the C27-G43 pair in the anticodon stem. The enzyme can use GTP in place of ATP for formation of N4-acetylcytidine [1].

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


1. Ikeuchi, Y., Kitahara, K. and Suzuki, T. The RNA acetyltransferase driven by ATP hydrolysis synthesizes N4-acetylcytidine of tRNA anticodon. EMBO J. 27 (2008) 2194-2203. [PMID: 18668122]

2. Chimnaronk, S., Suzuki, T., Manita, T., Ikeuchi, Y., Yao, M., Suzuki, T. and Tanaka, I. RNA helicase module in an acetyltransferase that modifies a specific tRNA anticodon. EMBO J. 28 (2009) 1362-1373. [PMID: 19322199]

[EC created 2011]

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