EC - Aminopyrimidine aminohydrolase

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IntEnz Enzyme Nomenclature


Accepted name:
aminopyrimidine aminohydrolase
Other names:
thiaminase II
tenA (gene name)
Systematic name:
4-amino-5-aminomethyl-2-methylpyrimidine aminohydrolase



Previously known as thiaminase II, this enzyme is involved in the regeneration of the thiamine pyrimidine from degraded products, rather than in thiamine degradation, and participates in thiamine salvage pathways.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ERGO , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0050334
CAS Registry Number: 9024-80-0
UniProtKB/Swiss-Prot: (23) [show] [UniProt]


  1. Fujita, A., Nose, Y. and Kuratani, K.
    Second type of bacterial thiaminase.
    J. Vitaminol. (Kyoto) 1 : 1-7 (1954). [PMID: 13243520]
  2. Ikehata, H.
    Purification of thiaminase II.
    J. Gen. Appl. Microbiol. 6 : 30-39 (1960).
  3. Toms, A. V., Haas, A. L., Park, J. H., Begley, T. P., Ealick, S. E.
    Structural characterization of the regulatory proteins TenA and TenI from Bacillus subtilis and identification of TenA as a thiaminase II.
    Biochemistry 44 : 2319-2329 (2005). [PMID: 15709744]
  4. Benach, J., Edstrom, W. C., Lee, I., Das, K., Cooper, B., Xiao, R., Liu, J., Rost, B., Acton, T. B., Montelione, G. T., Hunt, J. F.
    The 2.35 A structure of the TenA homolog from Pyrococcus furiosus supports an enzymatic function in thiamine metabolism.
    Acta Crystallogr. D Biol. Crystallogr.17618314 61 : 589-598 (2005). [PMID: 15858269]
  5. Jenkins, A. H., Schyns, G., Potot, S., Sun, G., Begley, T. P.
    A new thiamin salvage pathway.
    Nat. Chem. Biol. 3 : 492-497 (2007). [PMID: 17618314]
  6. Jenkins, A. L., Zhang, Y., Ealick, S. E., Begley, T. P.
    Mutagenesis studies on TenA: a thiamin salvage enzyme from Bacillus subtilis.
    Bioorg. Chem. 36 : 29-32 (2008). [PMID: 18054064]
  7. French, J. B., Begley, T. P., Ealick, S. E.
    Structure of trifunctional THI20 from yeast.
    Acta Crystallogr. D Biol. Crystallogr. 67 : 784-791 (2011). [PMID: 21904031]

[EC created 1961, modified 2011]