Spectrophotometric Characterization of the Action of Tyrosinase on p-Coumaric and Caffeic Acids: Characteristics of o-Caffeoquinone

Antonio Garcia-Jimenez, Jose Luis Munoz-Munoz, Francisco García-Molina, Jose Antonio Teruel-Puche, Francisco García-Cánovas

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

New methods are proposed to determine the activity of tyrosinase on caffeic and p-coumaric acids. Because o-quinone from caffeic acid is unstable in its presence, it has been characterized through spectrophotometric measurements of the disappearance of coupled reducing agents, such as nicotinamide adenine dinucleotide reduced form. It has also been characterized by a chronometric method, measuring the time that a known concentration of ascorbic acid takes to be consumed. The activity on p-coumaric acid has been followed by measuring the formation of o-quinone of caffeic acid at the isosbestic point originated between caffeic acid and o-caffeoquinone and measuring the formation of o-quinone at 410 nm, which is stable in the presence of p-coumaric acid (both of them in the presence of catalytic amounts of caffeic acid, maintaining the ratio between p-coumaric acid and caffeic acid constant; R = 0.025). The kcat value of tyrosinase obtained for caffeic acid was higher than that obtained for p-coumaric acid, while the affinity was higher for p-coumaric acid. These values agree with those obtained in docking studies involving these substrates and oxytyrosinase.

Original languageEnglish
Pages (from-to)3378-3386
Number of pages9
JournalJournal of Agricultural and Food Chemistry
Volume65
Issue number16
Early online date7 Apr 2017
DOIs
Publication statusPublished - 26 Apr 2017

Fingerprint Dive into the research topics of 'Spectrophotometric Characterization of the Action of Tyrosinase on p-Coumaric and Caffeic Acids: Characteristics of o-Caffeoquinone'. Together they form a unique fingerprint.

Cite this