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INTRACELLULAR LOCALIZATION OF TYROSINASE INHIBITOR IN AMELANOTIC AND MELANOTIC MALIGNANT MELANOMA
Author(s) -
HAMADA TOSHIO,
MISHIMA YUTAKA
Publication year - 1972
Publication title -
british journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.304
H-Index - 179
eISSN - 1365-2133
pISSN - 0007-0963
DOI - 10.1111/j.1365-2133.1972.tb05052.x
Subject(s) - tyrosinase , amelanotic melanoma , cytoplasm , melanoma , intracellular , chemistry , melanin , microbiology and biotechnology , cell , biochemistry , biology , cancer research , enzyme
Summary.— Intracellular distribution of the tyrosinase inhibitor in malignant melanoma cells has been investigated in order to elucidate the defect of melanization in the pigment cell cytoplasm and premelanosomes of amelanotic melanoma. We have found that the tyrosinase inhibitor has its highest activity in the cytoplasmic soluble fraction for both amelanotic and melanotic melanomata. However, inhibitor assay of melanoma subfractions reveals a distinct difference between the inhibitor activity of amelanotic and melanotic melanomata. Premelanosome‐containing subfractions of amelanotic melanomata contain much higher inhibitor activity than those of melanotic malignant melanomata. A high concentration of inhibitor seen in subfraction 3 which contains most of the total succinoxidase activity is found to be contained in the premelanosomes of this subfraction. It is suggested that the absence of melanization in the non‐premelanosomal cytoplasm of pigment cells and in the premelanosomes of tyrosinase containing amelanotic melanomata is directly related to the concentration of tyrosinase inhibitor in these compartments of the cells.