Publications by authors named "Mary Garcia-Molina"
Article Synopsis
- - Tyrosinase has three forms that change based on the copper oxidation state: met- (Em), oxy- (E(ox)), and deoxy- (Ed).
- - The enzyme converts Em to Ed by acting on a monophenol with O-diphenol as a reductant, and forms E(ox) when Ed binds with molecular oxygen.
- - The study shows that previous inhibitors of tyrosinase are actually true substrates, which can be identified by using hydrogen peroxide to form E(ox) from Em.
We characterize umbelliferone, a derivative of 2,4-dihydroxycoumaric acid, as a substrate of polyphenol oxidase. This enzyme hydroxylates umbelliferone to esculetin, its o-diphenol, and then oxidizes it to o-quinone. The findings show that umbelliferone, an intermediate in one of the coumarin biosynthesis pathways, may be transformed into its o-diphenol, esculetin, which is also an intermediate in the same pathway.
View Article and Find Full Text PDFCarbidopa and benserazide have been described as inhibitors of dopa decarboxylase and both have been used in the treatment of Parkinson's disease. Because of their chemical structure as polyphenols, these compounds can behave as substrates of tyrosinase and peroxidase. We demonstrate that these enzymes oxidize both substrates.
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