To isolate a novel iron-binding peptide, porcine plasma protein (PPP) was hydrolyzed using a commercial protease. The degree of hydrolysis and iron-binding capacity was determined using the trinitrobenzenesulfonic acid and orthophenanthroline method, respectively. The hydrolysates of blood plasma protein were then filtered using YM-3 membrane, and an iron-binding peptide was isolated using gel permeation, ion exchange, and normal phase high-performance liquid chromatography. The purified iron-binding peptide was identified to be a nona-peptide, Asp-Leu-Gly-Glu-Gln-Tyr-Phe-Lys-Gly (1055 Da) based on liquid chromatography/electrospray ionization (LC/ESI) tandem mass spectrum and a sequence of porcine plasma protein. (C) 2008 Elsevier Ltd. All rights reserved.