title: Serum albumin forms a lactoferrin-like soluble iron-binding complex in presence of hydrogen carbonate ions.
abstract: The iron-lactoferrin complex is a common food ingredient because of its iron-solubilizing capability in the presence of hydrogen carbonate ions. However, it is unclear whether the formation of a stable iron-binding complex is limited to lactoferrin. In this study, we investigated the effects of bovine serum albumin (BSA) on iron solubility and iron-catalyzed lipid oxidation in the presence of hydrogen carbonate ions. BSA could solubilize >100-fold molar equivalents of iron at neutral pH, exceeding the specific metal-binding property of BSA. This iron-solubilizing capability of BSA was impaired by thermally denaturing BSA at ≥ 70 °C for 10 min at pH 8.5. The resulting iron-BSA complex inhibited iron-catalyzed oxidation of soybean oil in a water-in-oil emulsion measured using the Rancimat test. Our study is the first to show that BSA, like lactoferrin, forms a soluble iron-binding complex in the presence of hydrogen carbonate ions.
authors.affiliation: Milk Science Research Institute, Megmilk Snow Brand Co., Ltd., 1-1-2 Minamidai, Kawagoe, Saitama 350-1165, Japan. Electronic address: hiroshi-ueno@beanstalksnow.co.jp.
authors.forename: Hiroshi M
authors.initials: HM
authors.lastname: Ueno
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Urazono
authors.forename: Toshiya
authors.initials: T
authors.lastname: Kobayashi
mesh_terms: D000975:Antioxidants / Q000737:chemistry; D001639:Bicarbonates / Q000737:chemistry*; D002712:Chlorides; D004655:Emulsions; D005290:Ferric Compounds; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*; D007781:Lactoferrin / Q000737:chemistry*; D050356:Lipid Metabolism; D010084:Oxidation-Reduction; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D012995:Solubility
chemical_list: D000975:Antioxidants; D001639:Bicarbonates; D002712:Chlorides; D004655:Emulsions; D005290:Ferric Compounds; D012710:Serum Albumin, Bovine; D007501:Iron; D007781:Lactoferrin; C024555:ferric chloride
keywords: Antioxidant activity; Complex; Iron; Serum albumin; Solubility