Transferrin is a blood plasma protein for iron ion delivery. It is a glycoprotein that binds iron very tightly but reversibly. Transferrin has a molecular weight of around 80 kDa and contains two specific high-affinity Fe3 binding sites. In serum-free medium iron carriers are essential supplements for the growth of commonly used mammalian cells.
The APO-form of Transferrin is almost free of bound iron. PromoCell Human Transferrin (APO) is a white lyophilized powder obtained from human plasma.
The HOLO-form of Transferrin is completely saturated with bound iron. PromoCell Human Transferrin (HOLO) is a pink to red lyophilized powder obtained from human plasma.