Figure 1. Schematic of the melanin synthetic pathway and enzymes involved that occur specifically in melanosomes.
Three enzymes are indispensable for the synthesis of melanin (eu- and pheo-melanogenesis as discussed in the text). Tyrosinase (TYR) is the rate-limiting enzyme for initial melanogenesis; DOPAchrome tautomerase (DCT) and tyrosinase-related protein 1 (TYRP1) are also involved in modulating eumelanogenesis. So far, no specific enzymes related to pheomelanogenesis have been detected. Other melanosome-specific proteins that help modulate melanin biosynthesis are listed.