Isolation and characterization of tyrosinase inhibitors and their differential action on melanogenic subcellular compartments in amelanotic and melanomas.

Further purification of highly active tyrosinase inhibitors by DEAE-Sephadex column chromatography has revealed that the mode of action of the inhibitors from melanomas with different melanogenic status is organelle specific. The inhibitor from amelanotic melanoma has a relatively strong suppressive effect on the tyrosinases in GERL and coated vesicle containing fractions. On the other hand, the inhibitor from melanotic melanoma has no substantial effect on these tyrosinases, although melanosomal tyrosinase is inhibited by both. The present evidence suggests that the defect of melanization in amelanotic melanoma in vivo is related to the tyrosinase inhibition of the smooth membrane system including GERL and coated vesicle by the highly active inhibitor characteristic of amelanotic melanoma.