title: Physico-chemical properties of different forms of bovine lactoferrin.
abstract: Three forms of bovine lactoferrin (Lf), apo-, native- and holo- with 0.9%, 12.9% and 99.7% iron content, respectively, were characterised for their physico-chemical properties. Colour, surface tension, thermal properties, particle charge and rheological behaviour of Lf were found to be affected by the form of Lf. The surface tension of Lf tends to decrease with decrease in iron content. The Circular Dichroism (CD) spectra confirmed that all forms of Lf had similar secondary structures while the tertiary structure was different for holo-Lf. The Differential Scanning Calorimeter (DSC) analysis showed that the apo- and holo-Lf in aqueous solution displayed thermal denaturation temperatures of 71±0.2 and 91±0.5 °C, respectively, suggesting that the iron saturation of Lf tends to increase its thermal stability. The study of particle charge properties (ζ-potential) in 1 mM KCl salt solution showed that apo-Lf reached the net charge of zero in the pH range 5.5-6.5 whereas native and holo-Lf in the pH range 8.0-9.0. The apparent viscosity of 1% (wt/wt) solution of the different forms of Lf showed no difference between apo- and native-Lf (≈1.4 mPas) while the value was significantly higher (2.38 mPas) for holo-Lf.
authors.affiliation: The University of Queensland, School of Agriculture and Food Sciences, Brisbane, QLD 4072, Australia. h.rai@uq.edu.au
authors.forename: Huma
authors.initials: H
authors.lastname: Bokkhim
authors.forename: Nidhi
authors.initials: N
authors.lastname: Bansal
authors.forename: Lisbeth
authors.initials: L
authors.lastname: Grøndahl
authors.forename: Bhesh
authors.initials: B
authors.lastname: Bhandari
mesh_terms: D000818:Animals; D002417:Cattle; D055598:Chemical Phenomena; D002942:Circular Dichroism; D006863:Hydrogen-Ion Concentration; D007781:Lactoferrin / Q000737:chemistry*; D055550:Protein Stability; D017433:Protein Structure, Secondary; D014783:Viscosity
chemical_list: D007781:Lactoferrin
keywords: Lactoferrin; Molecular confirmation; Physico-chemical properties; Rheological behaviour; Surface tension; Thermal denaturation