Alpha Fetoprotein (AFP) is a protein that is encoded by the gene AFP in humans. It is a plasma protein that is produced during fetal development by the yolk sac and the liver. AFP binds to copper, nickel, fatty acids and bilirubin and exists in monomeric, dimeric and trimeric forms. In the human fetus, AFP is the most abundant plasma protein, it binds estradiol to prevent the transport of this hormone across the placenta to the fetus. The major function of AFP is to prevent the virilization of female fetuses.
