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Updated: Apr 30, 2026

Monitoring the Reductive and Oxidative Half-Reactions of a Flavin-Dependent Monooxygenase using Stopped-Flow Spectrophotometry
Published on: March 18, 2012
Mechanistic aspects of the tyrosinase oxidation of hydroquinone
Christopher A Ramsden1, Patrick A Riley2
1Lennard-Jones Laboratories, School of Physical and Geographical Sciences, Keele University, Staffordshire ST5 5BG, UK.
Abstract:
Contradictory reports on the behaviour of hydroquinone as a tyrosinase substrate are reconciled in terms of the ability of the initially formed ortho-quinone to tautomerise to the thermodynamically more stable para-quinone isomer. Oxidation of phenols by native tyrosinase requires activation by in situ formation of a catechol formed via an enzyme generated ortho-quinone. In the special case of hydroquinone, catechol formation is precluded by rapid tautomerisation of the ortho-quinone precursor to catechol formation.
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