P protein is a protein that in humans is encoded by the OCA2 gene. OCA2 encodes the human homologue of the mouse p (pink-eyed dilution) gene. The P protein is believed to be an integral membrane protein involved in small molecule transport, specifically tyrosine - a precursor of melanin. Certain mutations in OCA2 result in type 2 oculocutaneous albinism. Another mutation in the OCA2 is found common to nearly all people with blue eyes, and has been hypothesized that all blue eyed humans share a s… (More on Oca2)