The influence of hydroquinone on tyrosinase kinetics.
In vitro studies, using combined spectrophotometry and oximetry together with hplc/ms examination of the products of tyrosinase action demonstrate that hydroquinone is not a primary substrate for the enzyme but is vicariously oxidised by a redox exchange mechanism in the presence of either catechol, L-3,4-dihydroxyphenylalanine or 4-ethylphenol. Secondary addition products formed in the presence of hydroquinone are shown to stimulate, rather than inhibit, the kinetics of substrate oxidation.
Gray Institute for Radiation Oncology & Biology, Department of Oncology, University of Oxford, Roosevelt Drive, Oxford OX3 7DQ, UK.
Michael R L
MR
Stratford
Christopher A
CA
Ramsden
Patrick A
PA
Riley
D002396:Catechols / Q000737:chemistry / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004295:Dihydroxyphenylalanine / Q000737:chemistry / Q000378:metabolism; D006873:Hydroquinones / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D013058:Mass Spectrometry; D014442:Monophenol Monooxygenase / Q000378:metabolism*; D010084:Oxidation-Reduction; D010092:Oximetry; D010636:Phenols / Q000737:chemistry / Q000378:metabolism; D013053:Spectrophotometry
D002396:Catechols; D006873:Hydroquinones; D010636:Phenols; D004295:Dihydroxyphenylalanine; C042291:4-ethylphenol; D014442:Monophenol Monooxygenase; C034221:catechol; C031927:hydroquinone