Human AFP Synthetic Peptide. AFP (Alpha Fetoprotein) is a major plasma protein produced by the yolk sac, intestinal tract and the liver during fetal life. AFP expression in adults is often associated with hepatoma or teratoma. However, hereditary persistence of AFP may also be found in individuals with no obvious pathology. The protein is thought to be the fetal counterpart of serum albumin, and AFP and albumin genes are present in tandem in the same transcriptional orientation on chromosome 4. AFP is found in monomeric, dimeric, and trimeric forms. AFP can also bind to copper ions, nickel ions, fatty acids and bilirubin. The level of AFP in amniotic fluid is used to measure renal loss of protein to screen for spina bifida and anencephaly.