Tyrosinase is a copper-containing metalloglycoprotein that catalyzes several steps in the melanin pigment biosynthetic pathway; the hydroxylation of tyrosine to L-3,4-dihydroxyphenylalanine (dopa), and the subsequent oxidation of dopa to dopaquinone. Mutations of the tyrosinase gene occur in various forms of albinism. Tyrosinase is one of the targets for cytotoxic T-cell recognition in melanoma patients. Clone T311 shows no cross-reaction with MAGE-1 and tyrosinase-related protein 1, TRP-1/gp75.1 Staining of melanomas with clone T311 showed tyrosinase in melanotic as well as amelanotic variants.1 Ab-1 is a useful marker for melanocytes and melanomas. Occasionally a minor band at 55kDa is also detected in Western Blotting.