Preparation of apolactoferrin with a very low iron saturation

Iron(III) removal from lactoferrin by an iron(III)-chelating resin with immobilized 3-hydroxy-2-methyl-4(1H)-pyridinone ligands was studied at physiological pH in the presence of citrate. The resin had a marked effect on the extent of iron removal. By using the iron(III)-chelating resin, removal of iron from lactoferrin was nearly complete in <24 h. Apolactoferrin with 4% iron saturation could be prepared conveniently from 100% or from 18% iron-saturated lactoferrin under mild conditions without affecting the iron-binding capacity of the protein. The iron saturation of the obtained apolactoferrin was much lower than that of the apolactoferrin prepared by reported methods.