caa a22 4500 445321377 CHVBK 20180317142705.0 cr unu---uuuuu 170323e20111201xx s 000 0 eng 10.1007/s10534-011-9470-1 doi (NATIONALLICENCE)springer-10.1007/s10534-011-9470-1 Heme-mediated binding of α-casein to ferritin: evidence for preferential α-casein binding to ferrous iron [Elektronische Daten] [Aya Usami, Masakazu Tanaka, Yasunaga Yoshikawa, Kiyotaka Watanabe, Hiromichi Ohtsuka, Koichi Orino] Bovine milk α-casein was identified as a ferritin-binding protein, and ferritin is known to be a heme-binding protein. In this study, we found that the binding of α-casein to bovine spleen ferritin in vitro was blocked by hemin, but not by iron-free hemin (protoporphyrin IX) or zinc-protoporphyrin IX, suggesting that the presence of iron in heme play a key role in this interaction. Indeed, the binding of α-casein to ferritin and biotinylated hemin was inhibited by adding excess ferrous ammonium sulfate (FAS). To further elucidate the binding mechanism of α-casein to biotinylated hemin, Ferrozine and nitrilotriacetic acid (NTA) were used as ferrous and ferric iron chelators, respectively. FAS-mediated inhibition of α-casein to biotinylated hemin was neutralized with Ferrozine, but not NTA, while FAS- as well as ferric chloride-mediated inhibition in their interaction was neutralized by NTA. The following ions also inhibited α-casein-biotinylated hemin binding in order of potency of inhibition: FAS (Fe2+)≪ferric chloride (Fe3+)<copper sulfate (Cu2+)<zinc sulfate (Zn2+)<manganese chloride (Mn2+)<calcium chloride (Ca2+)<magnesium sulfate (Mg2+). These results suggests that the binding of α-casein to ferritin is heme-mediated through direct binding of α-casein to iron in the heme on the surface of ferritin molecule, and that α-casein preferentially binds Fe2+ compared with any other metal ions, including Fe3+. Springer Science+Business Media, LLC., 2011 α-Casein nationallicence Ferritin nationallicence Heme nationallicence Iron nationallicence Milk nationallicence Usami Aya Laboratory of Veterinary Biochemistry, School of Veterinary Medicine, Kitasato University, 034-8628, Aomori, Japan aut Tanaka Masakazu Laboratory of Veterinary Biochemistry, School of Veterinary Medicine, Kitasato University, 034-8628, Aomori, Japan aut Yoshikawa Yasunaga Laboratory of Veterinary Biochemistry, School of Veterinary Medicine, Kitasato University, 034-8628, Aomori, Japan aut Watanabe Kiyotaka Laboratory of Veterinary Biochemistry, School of Veterinary Medicine, Kitasato University, 034-8628, Aomori, Japan aut Ohtsuka Hiromichi Laboratory of Large Animal Internal Medicine, School of Veterinary Medicine, Kitasato University, 034-8628, Aomori, Japan aut Orino Koichi Laboratory of Veterinary Biochemistry, School of Veterinary Medicine, Kitasato University, 034-8628, Aomori, Japan aut BioMetals Springer Netherlands 24/6(2011-12-01), 1217-1224 0966-0844 24:6<1217 2011 24 10534 https://doi.org/10.1007/s10534-011-9470-1 text/html Onlinezugriff via DOI 1 brief-communication jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10534-011-9470-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Usami Aya Laboratory of Veterinary Biochemistry, School of Veterinary Medicine, Kitasato University, 034-8628, Aomori, Japan aut NATIONALLICENCE 700 1- Tanaka Masakazu Laboratory of Veterinary Biochemistry, School of Veterinary Medicine, Kitasato University, 034-8628, Aomori, Japan aut NATIONALLICENCE 700 1- Yoshikawa Yasunaga Laboratory of Veterinary Biochemistry, School of Veterinary Medicine, Kitasato University, 034-8628, Aomori, Japan aut NATIONALLICENCE 700 1- Watanabe Kiyotaka Laboratory of Veterinary Biochemistry, School of Veterinary Medicine, Kitasato University, 034-8628, Aomori, Japan aut NATIONALLICENCE 700 1- Ohtsuka Hiromichi Laboratory of Large Animal Internal Medicine, School of Veterinary Medicine, Kitasato University, 034-8628, Aomori, Japan aut NATIONALLICENCE 700 1- Orino Koichi Laboratory of Veterinary Biochemistry, School of Veterinary Medicine, Kitasato University, 034-8628, Aomori, Japan aut NATIONALLICENCE 773 0- BioMetals Springer Netherlands 24/6(2011-12-01), 1217-1224 0966-0844 24:6<1217 2011 24 10534 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer