Transferrin is a monomeric glycoprotein found in plasma at an average concentration of 250 mg/100 ml. The Holo form of transferrin is iron saturated and also called Siderophilin. The specific iron-binding protein in plasma, it has a role in the transportation and distribution of iron among the body organs, in iron metabolism and prevention of iron loss via the kidneys. Stored in bone marrow as Tf-bound iron, it also possesses bacteriostatic and fungistatic activity. Clinically, decreases in transferrin are observed in congenital disorders, newborns, inflammatory diseases, hypoproteinemias and nephrotic syndrome; increases are found in pregnancy, iron-deficiency anemias, and inoculation hepatitis. Transferrin is required by all types of cells in cultures for maximal growth. It is, therefore, an important transport factor used in defined culture media. Each human transferrin molecule has the ability to carry two iron ions in the ferric form (Fe3 ). Dissolves in water at 10 mg per ml. Prepared from plasma shown to be non reactive for HbsAG, anti-HCV, anti-HBc, and negative for anti-HIV 1 & 2 by FDA approved tests. Total protein determination by the Lowry method. >95percent pure and shows only one major band corresponding to the molecular weight of Transferrin by SDS-PAGE. Add deionized water to original volume, aliquot and freeze unused portion.