IUBMB Enzyme Nomenclature


Accepted name: tRNA-uridine aminocarboxypropyltransferase

Reaction: S-adenosyl-L-methionine + a uridine in tRNA = S-methyl-5'-thioadenosine + a 3-[(3S)-3-amino-3-carboxypropyl]uridine in tRNA

Other name(s): S-adenosyl-L-methionine:tRNA-uridine 3-(3-amino-3-carboxypropyl)transferase; tapT (gene name); DTWD1 (gene name); DTWD2 (gene name); S-adenosyl-L-methionine:uridine47 in tRNAPhe 3-[(3S)-3-amino-3-carboxypropyl]transferase

Systematic name: S-adenosyl-L-methionine:uridine in tRNA 3-[(3S)-3-amino-3-carboxypropyl]transferase

Comments: 3-[(3S)-3-amino-3-carboxypropyl]uridine (acp3U) is a highly conserved modification found in tRNA core region in bacteria and eukaryotes that confers thermal stability on tRNA. The enzyme from the bacterium Escherichia coli catalyses the modification of uridine47 in the V-loop of tRNAs for Arg2, Ile1, Ile2, Ile2v, Lys, Met, Phe, Val2A, and Val2B. The human homologs DTWD1 and DTWD2 are responsible for acp3U formation at positions 20 and 20a, respectively, in the D-loop of several cytoplasmic tRNAs.

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


1. Nishimura, S., Taya, Y., Kuchino, Y. and Ohashi, Z. Enzymatic synthesis of 3-(3-amino-3-carboxypropyl)uridine in Escherichia coli phenylalanine transfer RNA: transfer of the 3-amino-acid-3-carboxypropyl group from S-adenosylmethionine. Biochem. Biophys. Res. Commun. 57 (1974) 702-708. [PMID: 4597321]

2. Takakura, M., Ishiguro, K., Akichika, S., Miyauchi, K. and Suzuki, T. Biogenesis and functions of aminocarboxypropyluridine in tRNA. Nat. Commun. 10 (2019) 5542. [PMID: 31804502]

3. Meyer, B., Immer, C., Kaiser, S., Sharma, S., Yang, J., Watzinger, P., Weiss, L., Kotter, A., Helm, M., Seitz, H.M., Kotter, P., Kellner, S., Entian, K.D. and Wohnert, J. Identification of the 3-amino-3-carboxypropyl (acp) transferase enzyme responsible for acp3U formation at position 47 in Escherichia coli tRNAs. Nucleic Acids Res. 48 (2020) 1435-1450. [PMID: 31863583]

[EC created 1984, modified 2014, modified 2020]

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