Subcellular Tyrosinase Activity and Site of Melanogenesis in Melanocytes
In mammals, melanin is synthesized in a specialized secretory cell known as the melanocyte. This cell is characterized by the presence of tyrosinase, which is responsible for the aerobic oxidation of L-tyrosine to dopa and to dopaquinone, which in turn is converted to indole-5,6-quinone. This monomer then is oxidized and polymerized to form a large polymer which is believed to be attached, through its quinone linkages, to amino or sulfhydryl groups of the protein matrix of the pigment granules [8, 10]. Recent electron microscopic studies show that the melanin granules appear to start in a region of the melanocyte associated with the Golgi membranes as hollow vesicles in which a tenuous material appears in the form of a folded lamella. This material is rapidly thickened and defined by the deposition of more dense material which is considered to be polymerized indole-5,6quinone, although the nature of this material is not yet thoroughly determined [2,22]. On the other hand, morphological and biochemical studies have revealed that in the secretory cell, the rough membranes and the smooth membranes which are main components of the small granule fraction when it is fractionated by biochemical procedures, were all engaged in the formation of secretory substances and in the secretory mechanisms .
KeywordsSucrose Sedimentation Lime Cyanide Macromolecule
Allfrey, V. G., A. E. Mirsky, and S. Osawa
: Protein synthesis in isolated cell nuclei. J. gen. Physiol. 40, 451–490 (1957).PubMedCrossRefGoogle Scholar
Birbeck, M. S. C.
: Electronmicroscopy of melanocytes. The fine structure of hair-bulb premelanosomes. Ann. N. Y. Acad. Sci. 100, 540–547 (1963).PubMedGoogle Scholar
Blols, JR., M. S., and R. F. Kallman
: The incorporation of C14 from 3,4¬dihydroxyphenylalanine-2’-C14 into the melanin of mouse melanomas. Cancer Res. 24, 863–868 (1964).Google Scholar
Dallner, G., S. Orrenius, and A. Bergstrand
: Isolation and properties of rough and smooth vesicles from rat liver. J. Cell Biol. 16, 426–430 (1962).CrossRefGoogle Scholar
Ernster, L., P. Siekevitz, and G. Palade
: Enzyme-structure relationships in the endoplasmic reticulum of rat liver; a morphological and biochemical study. J. Cell. Biol. 15, 541–562 (1962).PubMedCrossRefGoogle Scholar
Gianetto, R., and C. de Dove
: Tissue fractionation studies; comparative study of the binding of acid phosphatase, ß-glucuronidase and cathepsin by rat-liver particles. Biochem. J. 59, 433–438 (1955).PubMedGoogle Scholar
Greenberg, S. S., and M. J. Kopac
: Studies of gene action and melanogenic enzyme activity in melanomatous fishes. Ann. N. Y. Acad. Sci. 100, 887–923 (1963).PubMedGoogle Scholar
Harley Mason, J.
: Biosynthesis and structure of tyrosine melanin. In International Congress of Pure and Applied Chemistry XVII, München 1959. London: Butterworth 1960, p. 35–39.Google Scholar
Johnson, M. J.
: Isolation and properties of a pure yeast polypeptidase. J. Biol. Chem. 137, 575–586 (1941).Google Scholar
Mason, H. S.
: The chemistry of melanin. III. Mechanism of the oxidation of dihydroxyphenylalanine by tyrosinase. J. Biol. Chem. 172, 83–99 (1948).PubMedGoogle Scholar
Miyamoto, M., and T. B. Fitzpatrick
: On the nature of the pigment in retinal pigmented epithelium. Science 126, 449 (1957).PubMedCrossRefGoogle Scholar
Nakai, T., and P. Shusix
: Electronmicroscopic radioautography: the melanosome as a site of melanogenesis in neoplastic melanocytes. J. invest. Derm. 43, 267–269 (1964).PubMedGoogle Scholar
Ogata, K., I. Watanabe, T. Morita, and H. Sugano
: Decrease in the incorporating activity of liver ribosomes and the release of ribonucleic acid as a result of ultrasonic treatment. Biochim. biophys Acta. 55, 264–267 (1962).PubMedCrossRefGoogle Scholar
Palade, G. E., and P. Siekevitz
: Liver microsomes. An integrated morphological and biochemical study. J. biophys. biochem. Cytol. 2, 171–200 (1956).PubMedCrossRefGoogle Scholar
Peters, T., Jr.
: The biosynthesis of rat serum albumin. I. Properties of rat albumin and its occurrence in liver cell fraction. J. biol. Chem. 237, 1181–1185 (1962).Google Scholar
Rothschild, J. A.
: Sub-fraction of rat liver microsomes. Fed. Proc. 20, 145 (1961).Google Scholar
Schneider, W. C., and G. H. Hogeboom
: Intracellular distribution of enzymes. VII. The distribution of nucleic acids and adenosinetriphosphatase in normal mouse liver and mouse hepatoma. J. Nat. Cancer Inst. 10, 977–982 (1950).PubMedGoogle Scholar
Seiji, M., T. B. Fitzpatrick, R. T. Simpson, and M. S. C. Birbeck
: Chemical composition and terminology of specialized organelles (melanosomes and melanin granules) in mammalian melanocytes. Nature 197, 1082–1084 (1963).PubMedCrossRefGoogle Scholar
Seiji, M., and S. Iwashita
: Intracellular localization of tyrosinase in melanocyte. J. Biochem. 54, 103–106 (1963).PubMedGoogle Scholar
Seiji, M., and S. Iwashita
: On the site of melanin formation in melanocytes. J. Biochem. 54, 465–467 (1963).PubMedGoogle Scholar
Seiji, M., and K. Shimao
: Density gradient centrifugation. Japanese J. Biochem. 33, 435–441 (1961).Google Scholar
Seiji, M., and K. Shimao, M. S. C. Birbeck, and T. B. Fitzpatrick
: Subcellular localization of melanin biosynthesis. Ann. N. Y. Acad. Sci. 100, 497–544 (1963).PubMedGoogle Scholar
Siekevitz, P., and G. E. Palade
: A cytochemical study of the pancreas of the guinea pig. II. Functional variations in the enzymatic activity of microsomes. J. biophys. biochem. Cytol. 4, 401–410 (1958).CrossRefGoogle Scholar
Swanson, M. A.
: Glucose-6-phosphatase from liver. In: Method in Enzymology. Ed. S. P. Colowicx and H. O. Kaplan. New York: Academic Press 1955.Google Scholar
van Lancker, J. L., and R. L. Holtzer
: Tissue fractionation studies of mouse pancreas; intracellular distribution of nitrogen, deoxyribonucleic acid, ribonucleic acid, amylase, acid phosphatase, deoxyribonuclease and cytochrome oxidase. J. biol. Chem. 234, 2359–2363 (1959).Google Scholar
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