Reaction: thymine + 3 2-oxoglutarate + 3 O2 = uracil-5-carboxylate + 3 succinate + 3 CO2 + H2O (overall reaction)
(1a) thymine + 2-oxoglutarate + O2 = 5-hydroxymethyluracil + succinate + CO2
(1b) 5-hydroxymethyluracil + 2-oxoglutarate + O2 = 5-formyluracil + succinate + CO2 + H2O
(1c) 5-formyluracil + 2-oxoglutarate + O2 = uracil-5-carboxylate + succinate + CO2
Other name(s): thymine 7-hydroxylase; 5-hydroxy-methyluracil dioxygenase; 5-hydroxymethyluracil oxygenase
Systematic name: thymine,2-oxoglutarate:oxygen oxidoreductase (7-hydroxylating)
Comments: Requires Fe2+ and ascorbate. The enzyme, found in fungi, catalyses the oxidation of thymine to uracil 5-carboxylate as part of a thymidine salvage pathway.
Links to other databases: BRENDA, EXPASY, GENE, KEGG, MetaCyc, PDB, CAS registry number:
References:
1. Bankel, L., Holme, E., Lindstedt, G. and Lindstedt, S. Oxygenases involved in thymine and thymidine metabolism in Neurospora crassa. FEBS Lett. 21 (1972) 135-138. [PMID: 11946494]
2. Liu, C.-K., Hsu, C.-A. and Abbott, M.T. Catalysis of three sequential dioxygenase reactions by thymine 7-hydroxylase. Arch. Biochem. Biophys. 159 (1973) 180-187. [PMID: 4274083]
3. Warn-Cramer, B.J., Macrander, L.A. and Abbott, M.T. Markedly different ascorbate dependencies of the sequential α-ketoglutarate dioxygenase reactions catalyzed by an essentially homogeneous thymine 7-hydroxylase from Rhodotorula glutinis. J. Biol. Chem. 258 (1983) 10551-10557. [PMID: 6684117]
4. Smiley, J.A., Kundracik, M., Landfried, D.A., Barnes, V.R., Sr. and Axhemi, A.A. Genes of the thymidine salvage pathway: thymine-7-hydroxylase from a Rhodotorula glutinis cDNA library and iso-orotate decarboxylase from Neurospora crassa. Biochim. Biophys Acta 1723 (2005) 256-264. [PMID: 15794921]