Kinetic characterization of oxyresveratrol as a tyrosinase substrate

• Published in: IUBMB life Vol. 67; no. 11; pp. 828 - 836
• Main Authors: Ortiz‐Ruiz, Carmen Vanessa, Ballesta de los Santos, Manuel, Berna, Jose, Fenoll, Jose, Garcia‐Ruiz, Pedro Antonio, Tudela, Jose, Garcia‐Canovas, Francisco
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01-11-2015
• Subjects: alternative substrate; Fungal Proteins - antagonists & inhibitors; Fungal Proteins - chemistry; hydrogen peroxide; Hydrogen Peroxide - chemistry; Hydroxylation; kinetic characterization; Kinetics; Levodopa - chemistry; Monophenol Monooxygenase - antagonists & inhibitors; Monophenol Monooxygenase - chemistry; oxyresveratrol; Plant Extracts - chemistry; Stilbenes - chemistry; Substrate Specificity; tyrosinase; Tyrosine - chemistry; oxyresveratrol; kinetic characterization; alternative substrate; tyrosinase; hydrogen peroxide
• ISSN: 1521-6543; 1521-6551
• DOI: 10.1002/iub.1439

Oxyresveratrol is a stilbenoid described as a powerful inhibitor of tyrosinase and proposed as skin‐whitening and anti‐browning agent. However, the enzyme is capable of acting on it, considering it as a substrate, as it has been proved in the case of its analogous resveratrol. Tyrosinase hydroxylates the oxyresveratrol to an o‐diphenol and oxidizes the latter to an o‐quinone, which finally isomerizes to p‐quinone. For these reactions to take place the presence of the Eox (oxy‐tyrosinase) form is necessary. The kinetic analysis of the proposed mechanism has allowed the kinetic characterization of this molecule as a substrate of tyrosinase, affording a catalytic constant of 5.39 ± 0.21 sec−1 and a Michaelis constant of 8.65 ± 0.73 µM. © 2015 IUBMB Life, 67(11):828–836, 2015