title: Secretion of an aluminum chelator, 2-isopropylmalic acid, by the budding yeast, Saccharomyces cerevisiae.
abstract: An aluminum(III)-binding substance (ABS), that solubilizes Al(III) at neutral pH, was found to be secreted by Saccharomyces cerevisiae. A combination of anion exchange chromatography and preparative high performance liquid chromatography using an octadecylsilane (ODS) column separated ABS from the medium. The structure determination of ABS was performed using 1H and 13C NMR spectroscopy and heteronuclear multiple-bond correlation (HMBC) spectroscopy, and ABS was identified to be 2-isopropylmalic acid (2-iPMA). The structure was further confirmed using high resolution electrospray ionization mass spectrometry. Solubilization of otherwise sparingly soluble Al(III) by 2-iPMA at neutral pH indicated the binding of the compound with Al(III). This is supported by 27Al NMR spectrometry for a solution containing 10 mM Al(III) and 20 mM 2-iPMA at pH 6.6, where four Al(III) species were evident. Although the function of this compound is unclear, it might play a key role in Al detoxification.
authors.affiliation: Applied Biological Chemistry, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kobayashi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Edo
authors.forename: Kazuo
authors.initials: K
authors.lastname: Furihata
authors.forename: Etsuro
authors.initials: E
authors.lastname: Yoshimura
mesh_terms: D000535:Aluminum / Q000378:metabolism*; D002614:Chelating Agents / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008293:Malates / Q000737:chemistry* / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D012995:Solubility
chemical_list: C502920:2-isopropylmalic acid; D002614:Chelating Agents; D008293:Malates; D000535:Aluminum