title: Model studies on iron(III) ion affinity chromatography. II. Interaction of immobilized iron(III) ions with phosphorylated amino acids, peptides and proteins.
abstract: The chromatographic behaviour of phosphoamino acids, phosphopeptides and phosphoproteins and their non-phosphorylated counterparts was studied on Fe(III)-Chelating Sepharose and Fe(III)-Chelating Superose. The phosphorylated compounds, in contrast to their non-phosphorylated or dephosphorylated counterparts, adsorb to immobilized iron(III) ions at pH 5.5 and can be desorbed by an increase in pH. Phosphoamino acids were eluted at pH 6.5-6.7, whereas monophosphopeptides and phosphoprotamine eluted in the pH range 6.9-7.5. Molecules possessing clusters(s) of carboxylic groups are weakly retained (gamma-carboxyglutamic acid, Ala-Ser-Glu5) or bound (polyglutamic acid, beta-casein) to the immobilized iron(III) ions at pH 5.5. Dephosphorylated beta-casein was desorbed at pH 7.0, whereas for elution of native (non-dephosphorylated) beta-casein, phosphate buffer of pH 7.7 was required. The homopolymer of polyglutamic acid was desorbed in the pH range 6.0-6.3, whereas copolymers of glutamic acid and tyrosine require pH 7.0-7.3 or even phosphate buffer at pH 7.7 for elution.
authors.affiliation: Biochemical Separation Centre, Uppsala University, Sweden.
authors.forename: G
authors.initials: G
authors.lastname: Muszyńska
authors.forename: G
authors.initials: G
authors.lastname: Dobrowolska
authors.forename: A
authors.initials: A
authors.lastname: Medin
authors.forename: P
authors.initials: P
authors.lastname: Ekman
authors.forename: J O
authors.initials: JO
authors.lastname: Porath
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry*; D002412:Cations; D002846:Chromatography, Affinity / Q000379:methods*; D002853:Chromatography, Liquid; D007477:Ions; D007501:Iron / Q000737:chemistry*; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D010750:Phosphoproteins / Q000737:chemistry*; D010766:Phosphorylation
chemical_list: D000596:Amino Acids; D002412:Cations; D007477:Ions; D010455:Peptides; D010750:Phosphoproteins; D007501:Iron