title: Tyrosinase-Catalyzed Hydroxylation of 4-Hexylresorcinol, an Antibrowning and Depigmenting Agent: A Kinetic Study.
abstract: 4-Hexylresorcinol (HR) is a compound used in the food and cosmetic industries as an antibrowning and lightening agent. Its use is mainly attributed to its inhibitory effect on the enzyme tyrosinase. However, the enzyme hydroxylates HR to an o-diphenol, which it then oxidizes to an o-quinone, which rapidly isomerizes to p-quinone. For tyrosinase to act in this way, the Eox form (oxy-tyrosinase) must be present in the reaction medium, which can be brought about by (a) hydrogen peroxide, (b) ascorbic acid, or (c) catalytic concentrations of o-diphenol and a reductant (NADH) to maintain it constant. This work demonstrates that HR is a substrate of tyrosinase and proposes a mechanism for its action. Its kinetic characterization provides a catalytic constant of 0.85 ± 0.04 s(-1) and a Michaelis constant of 60.31 ± 6.73 μM.
authors.affiliation: †GENZ-Group of Research on Enzymology, Department of Biochemistry and Molecular Biology-A, ‡Group of Synthetic Organic Chemistry, Department of Organic Chemistry, and #Department of Analytical Chemistry, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, 30071 Murcia, Spain.
authors.forename: Carmen Vanessa
authors.initials: CV
authors.lastname: Ortiz-Ruiz
authors.affiliation: †GENZ-Group of Research on Enzymology, Department of Biochemistry and Molecular Biology-A, ‡Group of Synthetic Organic Chemistry, Department of Organic Chemistry, and #Department of Analytical Chemistry, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, 30071 Murcia, Spain.
authors.forename: Jose
authors.initials: J
authors.lastname: Berna
authors.affiliation: †GENZ-Group of Research on Enzymology, Department of Biochemistry and Molecular Biology-A, ‡Group of Synthetic Organic Chemistry, Department of Organic Chemistry, and #Department of Analytical Chemistry, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, 30071 Murcia, Spain.
authors.forename: Jose Neptuno
authors.initials: JN
authors.lastname: Rodriguez-Lopez
authors.affiliation: †GENZ-Group of Research on Enzymology, Department of Biochemistry and Molecular Biology-A, ‡Group of Synthetic Organic Chemistry, Department of Organic Chemistry, and #Department of Analytical Chemistry, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, 30071 Murcia, Spain.
authors.forename: Virginia
authors.initials: V
authors.lastname: Tomas
authors.affiliation: †GENZ-Group of Research on Enzymology, Department of Biochemistry and Molecular Biology-A, ‡Group of Synthetic Organic Chemistry, Department of Organic Chemistry, and #Department of Analytical Chemistry, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, 30071 Murcia, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Garcia-Canovas
mesh_terms: D000363:Agaricales / Q000201:enzymology; D055162:Biocatalysis; D005503:Food Additives / Q000737:chemistry*; D005656:Fungal Proteins / Q000737:chemistry*; D006604:Hexylresorcinol / Q000737:chemistry*; D006900:Hydroxylation; D007536:Isomerism; D007700:Kinetics; D014442:Monophenol Monooxygenase / Q000737:chemistry*; D010084:Oxidation-Reduction; D062327:Skin Lightening Preparations / Q000737:chemistry*
chemical_list: D005503:Food Additives; D005656:Fungal Proteins; D062327:Skin Lightening Preparations; D014442:Monophenol Monooxygenase; D006604:Hexylresorcinol
keywords: 4-hexylresorcinol; antibrowning; hydrogen peroxide; kinetic characterization; lightening; tyrosinase