Species of Origin: Purified from chicken egg white. Transferrins are iron binding transport proteins which can bind two Fe3+ ions in association with the binding of an anion, usually bicarbonate. It is responsible for the transport of iron from sites of absorption and heme degradation to those of storage and utilization. Serum transferrin may also have a further role in stimulating cell proliferation. Transferrin has a bacteriostatic function. Its concentration in avian egg is the highest concentration of any transferrin in vivo. Transferrin in liver is regulated by the iron levels but not in the oviduct. These two forms of transferrin (liver and oviduct) differ only by their carbohydrate composition.