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Kinetic study of the oxidation of 4‐hydroxyanisole catalyzed by tyrosinase
Author(s) -
Espína J. C.,
Varón R.,
Tudela J.,
GarcíaCánovasa Francisco
Publication year - 1997
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216549700202361
Subject(s) - tyrosinase , kinetic energy , butylated hydroxyanisole , catalysis , chemistry , catechol oxidase , combinatorial chemistry , biochemistry , enzyme , antioxidant , physics , peroxidase , polyphenol oxidase , quantum mechanics
Despite the importance of the substrate 4‐hydroxyanisole in melanoma therapy, the kinetics of its oxidation catalyzed by tyrosinase has never been properly characterized. This approach is reported here for the first time. The applicability to 4‐hydroxyanisole of the reaction mechanism of tyrosinase previously proposed for other monophenols has been corroborated. The Michaelis constant for the oxidation of 4‐hydroxyanisole catalyzed by mushroom tyrosinase was (62±1.5jt]μM at pH 7 and increased when the pH decreased, reaching a value of (195±5jt]μM at pH 5.5. However the maximum steady‐state rate, whose value was (0.54±0.01jt]μM/min, did not change with the pH. The apparent catalytic constant was (184±5jt]s‐1, around twenty three times higher than that previously described for L‐tyrosine (8 s‐l).