Quantitative assay of melanin in melanoma cells in culture and in tumors

A simple method has been developed for the quantitative fluorimetric determination of melanin. In these studies, we have used synthetic melanin prepared from l-dopa by mushroom tyrosinase and natural melanin present in B16 mouse melanoma cells grown in culture or as a solid tumor. In the assay procedure, the melanin is oxidatively degraded into soluble products by heating in an alkaline, dilute hydrogen peroxide solution under standard conditions. The resulting solution has a characteristic fluorescence which is quantitatively related to the melanin initially present. The assay is very sensitive and can be applied directly to tissues or cell cultures, without prior isolation of the melanin.