New assays for the tyrosine hydroxylase and dopa oxidase activities of tyrosinase
Open Access
- 1 June 1991
- journal article
- Published by Wiley in European Journal of Biochemistry
- Vol. 198 (2) , 317-326
- https://doi.org/10.1111/j.1432-1033.1991.tb16018.x
Abstract
New assays for the tyrosine hydroxylase and dopa oxidase activities of tyrosinase (EC 1.14.18.1) have been developed. The tyrosine hydroxylase assay uses L-[carboxy-14C]tyrosine as the substrate. 14CO2 is released from the products of the hydroxylation and further metabolism of L-[carboxy-14C]tyrosine by incubation with ferricyanide, and measured radiometrically. D-Dopa is a preferable cofactor to L-dopa for the assay. Dopa oxidase activity is measured spectrophotometrically. Dopaquinone, produced on the oxidation of L-dopa, reacts with Besthorn's hydrazone (3-methyl-2-benzothiazolinone hydrazone) to form a pink pigment with an absorbance maximum at 505 nm. Details of the optimisation of conditions for the assays and their specificities for the two enzyme activities are described.Keywords
This publication has 38 references indexed in Scilit:
- Assays for Mammalian Tyrosinase: A Comparative StudyPigment Cell Research, 1988
- Dopa Oxidase Activity in Human Hairbulbs Measured by High-Performance Liquid ChromatographyJournal of Investigative Dermatology, 1986
- Mammalian Tyrosinase Catalyzes Three Reactions in the Biosynthesis of MelaninScience, 1982
- Demonstration of Tyrosinase in the Vitiligo Skin of Human Beings by a Sensitive Fluorometric Method as Well as by 14C(U)-L-Tyrosine Incorporation into MelaninJournal of Investigative Dermatology, 1982
- A tumor-specific membrane phosphoprotein marker in human cell hybridsCell, 1981
- A Rapid and Sensitive Method for the Quantitation of Microgram Quantities of Protein Utilizing the Principle of Protein-Dye BindingAnalytical Biochemistry, 1976
- A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye bindingAnalytical Biochemistry, 1976
- Tyrosinase in the skin of albino hamsters and miceNature, 1974
- Subcellular Demonstration of Peroxidatic Oxidation of Tyrosine to Melanin Using Dihydroxyfumarate as Cofactor in Mouse Melanoma CellsJournal of Investigative Dermatology, 1973
- Tyrosine hydroxylation catalyzed by mammalian tyrosinase: An improved method of assayBiochemical and Biophysical Research Communications, 1964