3-methyl-2-benzothiazolone-hydrazone has been researched along with mequinol* in 3 studies
3 other study(ies) available for 3-methyl-2-benzothiazolone-hydrazone and mequinol
Article | Year |
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Zymography of monophenolase and o-diphenolase activities of polyphenol oxidase.
Topics: Anisoles; Benzothiazoles; Caffeic Acids; Catechol Oxidase; Edible Grain; Hydrazones; Oxidoreductases; Quinones; Spectrophotometry; Thiazoles | 2002 |
Kinetic study of the oxidation of 3-hydroxyanisole catalysed by tyrosinase.
Tyrosinase hydroxylates 3-hydroxyanisole in the 4-position. The reaction product accumulates in the reaction medium with a lag time (tau) which diminishes with increasing concentrations of enzyme and lengthens with increasing concentrations of substrate, thus fulfilling all the predictions of the mechanism proposed by us for 4-hydroxyphenols. The kinetic constants obtained, kcatM = (46.87 +/- 2.06) s-1 and KmM = (5.40 +/- 0.60) mM, are different from those obtained with 4-hydroxyanisole, kcatM = (184.20 +/- 6.1) s-1 and KmM = (0.08 +/- 0.004) mM. The catalytic efficiency, kcatM/KmM is, therefore, 265.3 times greater with 4-hydroxyanisole. The possible rate-determining steps for the reaction mechanism of tyrosinase on 3- and 4-hydroxyanisole, based on the NMR spectra of both monophenols, are discussed. These possible rate-determining steps are the nucleophilic attack of hydroxyl's oxygen on the copper and the electrophilic attack of the peroxide on the aromatic ring. Both steps may be of similar magnitude, i.e. take place in the same time scale. Topics: Agaricales; Anisoles; Benzothiazoles; Catalysis; Hydrazones; Hydroxylation; Isomerism; Kinetics; Monophenol Monooxygenase; Nuclear Magnetic Resonance, Biomolecular; Oxidation-Reduction; Thiazoles | 2000 |
Kinetic study of the oxidation of 4-hydroxyanisole catalyzed by tyrosinase.
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 +/- 1.5) microM at pH 7 and increased when the pH decreased, reaching a value of (195 +/- 5) microM at pH 5.5. However the maximum steady-state rate, whose value was (0.54 +/- 0.01) microM/min, did not change with the pH. The apparent catalytic constant was (184 +/- 5) s-1, around twenty three times higher than that previously described for L-tyrosine (8 s-1). Topics: Anisoles; Benzothiazoles; Catalysis; Hydrazones; Hydrogen-Ion Concentration; Kinetics; Monophenol Monooxygenase; Oxidation-Reduction; Phenols; Regression Analysis; Spectrophotometry; Substrate Specificity; Thiazoles | 1997 |