Demonstration of dopa oxidase activity by purified mammalian superoxide dismutase using polyacrylamide gel electrophoretic separation
Tóm tắt
Purified bovine erythrocyte superoxide dismutase (SOD) was separated by polyacrylamide gel electrophoresis. Gels which were stained for protein showed a single major band (Rx-0.41). Gels which were stained for SOD activity showed a single achromatic band (Rx-0.41) and gels which were stained for dopa oxidase activity also showed a single grey-black band (Rx-0.41). Rx values of other oxidases (horseradish peroxidase, mushroom tyrosinase, catalase and melanoma “tyrosinase” (L-dopa Oxidase) were significantly different from that of SOD. The dopa oxidase activity of SOD may be important as an alternative pathway for melanin synthesis with resultant free radical quenching by melanin and its intermediates. This secondary function is in addition to its primary function as a superoxide dismutase. These functions may be interrelated in some circumstances when L-dopa acts as the proton donor of the dismutase reaction:
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Tài liệu tham khảo
Harmon, D.: Prolongation of the normal lifespan and inhibition of spontaneous cancer by antioxidants. J. Gerontol., 16: 247–254, 1964.
Harmon, D.: Role of free radicals in mutation cancer aging and the maintainence of life. Radiation Res., 16: 753–763, 1962.
Harmon, D.: Free radical theory of aging: effect of the amount and degree of unsaturation of dietary fat on mortality rate. J. Gerontol., 26: 451–457, 1971.
Harmon, D., Hendricks, S., Eddy, D. E., Seibold, J.: Free radical theory of aging: effect of dietary fat on central nervous system function. J. Am. Geriatrics Soc., 24: 301–307, 1976.
Mead, J. F.: Free radical mechanisms of lipid damage and consequences for cellular membranes, in Free Radicals in Biology, Vol. 1, edited by Pryor, W. A., New York, Academic Press, 1976, pp. 51–68.
Foote, C. S.: Photosensitized oxidation and singlet oxygen: consequences in biological systems, in Free Radicals in Biology, Vol. 2, edited by Pryor, W. A., New York, Academic Press, 1976, pp. 85–133.
Emanuel, H. M.: Free radicals and the action of inhibitors of free radical processes under pathological states and aging in living organisms and in man. Quart. Rev. Biophys., 9: 283–307, 1976.
Bloch, B.: “Das problem der pigmentbildung in der haut”, Arch. Dermatol. Syph., 124: 129–208, 1917.
Hogeboom, G. H. and Adams, M. H.: Mammalian tyrosinase and dopa oxidase. J. Biol. Chem., 145: 273–279, 1942.
Lerner, A. B., Fitzpatrick, T. B., Calkins, E. and Summerson, W. H.: Mammalian tyrosinase; preparation and properties. J. Biol. Chem., 178: 185–195, 1949.
Okun, M., Edelstein, L., Or, N., Hamada, G., Donnellan, B.: Histochemical studies of conversion of tyrosine and dopa to melanin mediated by mammalian peroxidase. Life Sci., 9,II: 491–505, 1970.
Okun, M., Edelstein, L., Or, N., Hamada, G., Donnellan, B.: The role of peroxidase vs. the role of tyrosinase in enzymatic conversion of tyrosine to melanin in melanocytes, mast cells and eosinophils: an autoradiographic-histochemical study. J. Invest, Dermatol., 55: 1–12, 1970.
Okun, M., Edelstein, L., Or, N., Hamada, G., Donnelian, B., Lever, W.: Histochemical differentiation of peroxidase-mediated from tyrosinase-mediated melanin formation in mammalian tissues: the biologic significance of peroxidase-mediated oxidation of tyrosine to melanin. Histochem., 23: 295–301, 1970.
Okun, M., Edelstein, L., Patel, R., Donnellan, B.: A revised concept of mammalian melanogenesis: the possible synergistic functions of aerobic dopa oxidase and peroxidase, a review. Yale J. Biol. Med., 46: 535–540, 1973.
Edelstein, L., Cariglia, N., Okun, M., Patel, R., Smucker, D.: Inability of murine melanoma melanosomal “tyrosinase” (L-Dopa Oxidase) to oxidize tyrosine to melanin in polyacrylamide gel systems. J. Invest. Dermatol., 64: 364–370, 1975.
Patel, R., Okun, M., Edelstein, L., Epstein, D.: Biochemical studies of the peroxidase-mediated oxidation of tyrosine to melanin: demonstration of the hydroxylation of tyrosine by plant and human peroxidases. Biochem. J., 124: 439–441, 1971.
Patel, R. P., Okun, M. R., Yee, W. A., Wilgram, G. F., Edelstein, L. M.: Inability to murine melanoma “tyrosinase” (Dopa Oxidase) to oxidize tyrosine in the presence or absence of dopa or dihydroxyfumarate cofactor. J. Invest. Derm., 61: 55–59, 1973.
Salin, M. L. and McCord, J. M.: Superoxide dismutase in polymorphonuclear leukocytes. J. Clin. Invest., 54: 1005–1009, 1974.
Davis, B.: Disc gel electrophoresis. Ann. N. Y. Acad. Sci., 121: 404–427, 1964.
Beauchamp, C. and Fridovich, I.: Superoxide dismutase: improved assays and an assay applicable to acrylamide gels. Anal. Biochem., 4: 276–287, 1971.
Gregory, E. M. and Fridovich, I.: Visualization of catalase on acrylamide gels. Anal. Biochem., 58: 57–62, 1974.