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Lookup NU author(s): Dr Jose Munoz Munoz
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© 2017 American Chemical Society. 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.
Author(s): Garcia-Jimenez A, Munoz-Munoz JL, Garcia-Molina F, Teruel-Puche JA, Garcia-Canovas F
Publication type: Article
Publication status: Published
Journal: Journal of Agricultural and Food Chemistry
Year: 2017
Volume: 65
Issue: 16
Pages: 3378-3386
Print publication date: 26/04/2017
Online publication date: 07/04/2017
Acceptance date: 07/04/2017
ISSN (print): 0021-8561
ISSN (electronic): 1520-5118
Publisher: American Chemical Society
URL: https://doi.org/10.1021/acs.jafc.7b00446
DOI: 10.1021/acs.jafc.7b00446
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