1. Tyrosinase is a copper-containing enzyme responsible for the production of melanin pigment throughout the phylogenetic spectrum. 2. In mammals, tyrosinase is a glycosylated enzyme found specifically in melanocytes--cells functional in the production and secretion of pigment granules. 3. Although many factors determine the type, quantity and quality of the melanin produced, tyrosinase activity is the critical factor that ultimately regulates melanogenesis.