DCT and oculocutaneous albinism: To further understanding of the melanogenesis pathway and enhance studies on treatments targeting this pathway for diseases such as OCA, we purified human recombinant tyrosinases involved in regulating the melanin pathway, isolated key substrates, and characterized the diphenol oxidase activity of tyrosinase and confirmed the activity of TYRP1 and TYRP2 to develop an in vitro model.