Inactivation mechanism of tyrosinase in mouse melanoma.
Tyrosinase [EC 1.14.18.1] isolated from mouse melanoma was inactivated during the dopa-tyrosinase reaction. When ascorbate was added to the reaction system, in which dopa-quinone is immediately converted back to dopa by ascorbate thus preventing the formation of melanin, tyrosinase inactivation similarly occurred. If superoxide anions (O2-) or singlet oxygens (1O2), are generated during the reaction they can attack the enzyme protein to be inactivated. Therefore an estimate was made with scavengers for oxygen radicals and with a liquid scintillation counter but neither was detectable. Thus the inactivation involved is not due to reaction products nor oxygen
Tomita
Y
Y
Department of Dermatology, Tohoku University School of Medicine, Sendai, Miyagi 980, Japan.
Seiji
M
M
D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology*; D004195:Disease Models, Animal; D008543:Melanins / Q000096:biosynthesis; D008544:Melanocytes / Q000201:enzymology; D008546:Melanoma, Experimental / Q000201:enzymology*; D051379:Mice; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000494:pharmacology; D012680:Sensitivity and Specificity; D013481:Superoxides / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D008543:Melanins; D017382:Reactive Oxygen Species; D013481:Superoxides; D014442:Monophenol Monooxygenase; D001205:Ascorbic Acid