T. Nakayama, T. Sato, Y. Fukui
Jun 15, 2001
Citations
5
Influential Citations
107
Citations
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Journal
FEBS Letters
Abstract
Aureusidin synthase, which plays a key role in the yellow coloration of snapdragon flowers, is a homolog of plant polyphenol oxidase (PPO). The enzyme specifically acted on chalcones with a 4‐monohydroxy or 3,4‐dihydroxy B‐ring to produce aurones, for whose production the oxidative cyclization of chalcones must be preceded by 3‐oxygenation. However, it exhibited virtually no PPO activity toward non‐chalcone phenolics. The enzyme was competitively inhibited by phenylthiourea, a specific PPO inhibitor. These results led us to propose a mechanism of aurone synthesis by aureusidin synthase on the basis of known PPO‐catalyzed reactions and conclude that the enzyme is a chalcone‐specific PPO specialized for aurone biosynthesis.