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Kinetic characterization of oxyresveratrol as a tyrosinase substrate
Carmen Vanessa Ortiz-Ruiz1, Manuel Ballesta de Los Santos1, Jose Berna2
1GENZ: Grupo De Investigación Enzimología, Departamento De Bioquímica Y Biología Molecular-A, Facultad De Biología, Campus De Excelencia Internacional "Mare Nostrum", Universidad De Murcia, Murcia, Spain.
Abstract:
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.
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