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In enzymology, a leucocyanidin oxygenase (EC 1.14.11.19) is an enzyme that catalyzes the chemical reaction

leucocyanidin + 2-oxoglutarate + O₂ ${\displaystyle \rightleftharpoons }$ cis- and trans-dihydroquercetins + succinate + CO₂ + 2 H₂O

The 3 substrates of this enzyme are leucocyanidin, 2-oxoglutarate, and O₂, whereas its 5 products are cis-dihydroquercetin, trans-dihydroquercetin, succinate, CO₂, and H₂O.

This enzyme belongs to the family of oxidoreductases, specifically those acting on paired donors, with O2 as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derived from O2 with 2-oxoglutarate as one donor, and incorporation of one atom o oxygen into each donor. The systematic name of this enzyme class is leucocyanidin,2-oxoglutarate:oxygen oxidoreductase. This enzyme is also called leucoanthocyanidin dioxygenase (LDOX) or anthocyanidin synthase (ANS). This enzyme participates in flavonoid biosynthesis.

In a broader way, leucocyanidin oxygenase uses flavan-3,4-diols (leucoanthocyanidins) to produce 3-hydroxyanthocyanidins. The gene encoding the enzyme (PpLDOX) has been identified in peach and expression has been studied in Vitis vinifera.

Structural studies

As of late 2007, only one structure, in Arabidopsis thaliana, has been solved for this class of enzymes, with the PDB accession code 2BRT.

References

1. "leucoanthocyanidin dioxygenase - Definition". mondofacto. Archived from the original on 2012-03-04.
2. Ogundiwin E, Peace C, Nicolet C, Rashbrook V, Gradziel T, Bliss F, Parfitt D, Crisosto C (July 2008). "Leucoanthocyanidin dioxygenase gene (PpLDOX): a potential functional marker for cold storage browning in peach". Tree Genetics & Genomes. 4 (3): 543–54. doi:10.1007/s11295-007-0130-0. S2CID 22579882.
3. Gollop R, Farhi S, Perl A (August 2001). "Regulation of the leucoanthocyanidin dioxygenase gene expression in Vitis vinifera". Plant Science. 161 (3): 579–588. doi:10.1016/S0168-9452(01)00445-9.

Further reading

• Saito K, Kobayashi M, Gong Z, Tanaka Y, Yamazaki M (1999). "Direct evidence for anthocyanidin synthase as a 2-oxoglutarate-dependent oxygenase: molecular cloning and functional expression of cDNA from a red forma of Perilla frutescens". Plant J. 17 (2): 181–9. doi:10.1046/j.1365-313X.1999.00365.x. PMID 10074715.
• Schofield CJ, Prescott AG (2000). "Are anthocyanidins the immediate products of anthocyanidin synthase?". Chem. Commun. (24): 2473–2474. doi:10.1039/b007594i.
• CJ; Nakajima, J; Welford, RW; Yamazaki, M; Saito, K; Schofield, CJ (2004). "Mechanistic studies on three 2-oxoglutarate-dependent oxygenases of flavonoid biosynthesis: anthocyanidin synthase, flavonol synthase, and flavanone 3beta-hydroxylase". J. Biol. Chem. 279 (2): 1206–16. doi:10.1074/jbc.M309228200. PMID 14570878.

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