title: Metal chelates of 2-hydroxy-4-methylthiobutanoic acid in animal feeding: preliminary investigations on stability and bioavailability.
abstract: The alpha-hydroxyacid 2-hydroxy-4-methylthiobutanoic acid (the so-called methionine hydroxy-analogue, MHA), largely used in animal nutrition as a source of methionine, forms stable metal chelates with divalent metals of formula [[CH(3)SCH(2)CH(2)CH(OH)COO](2)M].ZnH(2)O. Protonation and zinc(II) complex formation constants have been determined by pH-metry at 25 degrees C; the ternary system Zn(2+)/MHA/glycine was also studied by pH-metry and the formation constant of the species [ZnLA] was determined [log beta=6.57(11)]. Experiments in vitro with human intestinal CACO-2 cells indicated that the MHA/Fe chelate was taken up by the cells without any apparent toxic effect.
authors.affiliation: GIAF Chemistry Department, University of Parma, Parco Area delle Scienze 17/A, 43100 Parma, Italy. predieri@unipr.it
authors.forename: Giovanni
authors.initials: G
authors.lastname: Predieri
authors.forename: Matteo
authors.initials: M
authors.lastname: Tegoni
authors.forename: Enrico
authors.initials: E
authors.lastname: Cinti
authors.forename: Giuliano
authors.initials: G
authors.lastname: Leonardi
authors.forename: Simonetta
authors.initials: S
authors.lastname: Ferruzza
mesh_terms: D000821:Animal Feed; D000818:Animals; D001682:Biological Availability; D018938:Caco-2 Cells; D004355:Drug Stability; D005290:Ferric Compounds / Q000737:chemistry* / Q000493:pharmacokinetics*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007502:Iron Chelating Agents / Q000737:chemistry / Q000493:pharmacokinetics; D008715:Methionine / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000493:pharmacokinetics*; D011199:Potentiometry / Q000379:methods; D011522:Protons; D015032:Zinc / Q000737:chemistry* / Q000493:pharmacokinetics*
chemical_list: D005290:Ferric Compounds; D007502:Iron Chelating Agents; D011522:Protons; C008391:alpha-hydroxy-gamma-methylmercaptobutyric acid; D008715:Methionine; D015032:Zinc