title: Unexpected differences in the behavior of ovotransferrin at the air-water interface at pH 6.5 and 8.0.
abstract: Adsorption of purified apo-ovotransferrin at the air-water interface was studied by ellipsometry, surface tension, polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS), and shear elastic constant measurements. No significant difference was observed between pH 6.5 and 8.0 as regards the final value of surface concentration and surface pressure. However at low concentration, a weak barrier to adsorption is evidenced at pH 6.5 and confirmed by PM-IRRAS measurements. At a pH where the protein net charge is negative (pH 8.0), the behavior of ovotransferrin at the air-water interface is more influenced by charge effects rather than bulk concentration effects. At this pH, the interface exhibits a low shear elastic constant and a spectral signature not usual for globular proteins.
authors.affiliation: INRA, UMR1253 Science et Technologie du Lait et de l'Œuf, F-35042 Rennes, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Le Floch-Fouéré
authors.forename: Stéphane
authors.initials: S
authors.lastname: Pezennec
authors.forename: Michel
authors.initials: M
authors.lastname: Pézolet
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Rioux-Dubé
authors.forename: Anne
authors.initials: A
authors.lastname: Renault
authors.forename: Sylvie
authors.initials: S
authors.lastname: Beaufils
mesh_terms: D000327:Adsorption; D000388:Air; D000818:Animals; D002645:Chickens; D003207:Conalbumin / Q000737:chemistry*; D004548:Elasticity; D006863:Hydrogen-Ion Concentration; D011487:Protein Conformation; D013055:Spectrophotometry, Infrared; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water; D003207:Conalbumin