EC Number   |
Natural Substrates |
|---|
   1.21.3.6 | 2 2',3,4,4',6'-pentahydroxychalcone + O2 |
- |
| 1.21.3.6 | 2',3,4,4',6'-pentahydroxychalcone + 1/2 O2 |
- |
| 1.21.3.6 | 2',4',6',4-tetrahydroxychalcone + O2 |
- |
| 1.21.3.6 | 2',4,4',6'-tetrahydroxychalcone + O2 |
- |
| 1.21.3.6 | 2',4,4',6'-tetrahydroxychalcone + O2 |
key intermediate in the general flonoid metabolism |
| 1.21.3.6 | more |
pathway, overview |
| 1.21.3.6 | more |
chalcone-specific polyphenol oxidase specialized for aurone biosynthesis |
| 1.21.3.6 | more |
enzyme plays a key role in the yellow coloration of flowers, enzyme is a homologue of plant polyphenol oxidase |
| 1.21.3.6 | more |
substrate specificity allows elucidation of a likely mechanism of aurone formation from 2,4,6,4-tetrahydroxychalcone or PHC involving both tyrosinase and catechol oxidase activities of the Antirrhinum majus PPO, pathway overview. Starting with THC, tyrosinase and catechol oxidase activity, EC 1.14.18.1, result in 3-hydroxylation and formation of the corresponding o-quinone. Whether aureusidine synthase PPO carries out the 3-hydroxylation reaction in vivo, or whether a cytochrome P450 chalcone 3-hydroxylase is also involved is not definitively established. Aureusidine synthase likely forms the same quinone from 2',3,4,4',6'-pentahydroxychalcone without the need for the 3-hydroxylation step. The resulting quinone is predicted to undergo a 2-step non-enzyme mediated rearrangement to form aureusidin |
