title: Singlet oxygen generation during the oxidation of L-tyrosine and L-dopa with mushroom tyrosinase.
abstract: The generation of singlet oxygen during the oxidation of tyrosine and L-dopa using mushroom tyrosinase in a phosphate buffer (pH 7.4), the model of melanin synthesis in melanocytes, was examined. The reaction was performed in the presence of 2,2,6,6-tetramethyl-4-piperidone (4-oxo-TEMP), an acceptor of singlet oxygen and the electron spin resonance (ESR) of the spin adduct, 4-oxo-2,2,6,6-tetramethyl-1-piperidinyloxy (4-oxo-TEMPO), was measured. An increase in the ESR signal attributable to 4-oxo-TEMPO was observed during the oxidation of tyrosine and L-dopa with tyrosinase, indicating the generation of singlet oxygen. The results suggest that (1)O2 generation via tyrosinase-catalyzed melanin synthesis occurs in melanocyte.
authors.affiliation: Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259-G1-14, Nagatsuta-cho, Midori-ku, Yokohama 226-8502, Japan.
authors.forename: Akimitsu
authors.initials: A
authors.lastname: Miyaji
authors.affiliation: Department of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259-G1-25 Nagatsuta-cho, Midori-ku, Yokohama 226-8502, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kohno
authors.affiliation: Showa Pharmaceutical University, 3-3165 Higashi-tamagawagakuen, Machida, Tokyo 194-8543, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Inoue
authors.affiliation: Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259-G1-14, Nagatsuta-cho, Midori-ku, Yokohama 226-8502, Japan. Electronic address: tbaba@chemenv.titech.ac.jp.
authors.forename: Toshihide
authors.initials: T
authors.lastname: Baba
mesh_terms: D000363:Agaricales / Q000201:enzymology; D004578:Electron Spin Resonance Spectroscopy; D045563:Indolequinones / Q000378:metabolism; D007980:Levodopa / Q000378:metabolism*; D008543:Melanins / Q000096:biosynthesis / Q000378:metabolism; D014442:Monophenol Monooxygenase / Q000378:metabolism*; D010084:Oxidation-Reduction; D010880:Piperidines / Q000032:analysis / Q000378:metabolism; D026082:Singlet Oxygen / Q000378:metabolism*; D013481:Superoxides / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism*
chemical_list: C553894:4-oxo-2,2,6,6-tetramethyl-1-piperidinyloxyl; D045563:Indolequinones; D008543:Melanins; D010880:Piperidines; D013481:Superoxides; D026082:Singlet Oxygen; C001123:dopachrome; D014443:Tyrosine; D007980:Levodopa; D014442:Monophenol Monooxygenase
keywords: ESR; Oxidative stress; Singlet oxygen; Tyrosinase