Properties of a heparin-binding peptide derived from bovine lactoferrin

A heparin-binding peptide was isolated from a proteolytic hydrolysate of bovine lactoferrin by affinity chromatography using an immobilized heparin column. Analysis of amino acid sequences at the N-terminus showed that this heparin-binding peptide is derived from the region beginning at the 17th amino acid residue of the bovine lactoferrin sequence. The molecular mass of this peptide was 3195.5 as measured by matrix-assisted laser desorption-time of flight mass spectrometry. This peptide is the same as the bactericidal peptide lactoferricin B. In an aqueous environment, this peptide displays mainly a beta-sheet structure and an unordered structure as assessed by measurements of circular dichroism spectra. When this peptide was mixed with heparin, a distinct spectral change was induced because of conformational alteration of the peptide. This spectral change was reversible. Analysis of data from peptide synthesis indicated that binding by the sequence Arg28-Met29-Lys30-Lys31 of bovine lactoferrin is significant and that there is a synergistic contribution from Lys18-Cys19-Arg20-Arg21, and Arg38-Arg39.