Complex Formation Between Ca(II), Mg(II), Al(III) Ions and Salicylglycine

For modelling the interactions of proteins/peptides with hard metal ions the complex formation of salicylglycine (SalGly) with Ca(II), Mg(II) and AI(III) ions was studied in aqueous solution using pH-potentiometric and UV-vis spectroscopic techniques. Al(III) ion was found to form more stable comple...

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Bibliographic Details
Published in:Bioinorganic Chemistry and Applications 2003-01, Vol.2003 (3-4), p.321-332
Main Authors: Kilyen, Melinda, Labadi, Imre, Tombacz, Etelka, Kiss, Tamas
Format: Article
Language:English
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Summary:For modelling the interactions of proteins/peptides with hard metal ions the complex formation of salicylglycine (SalGly) with Ca(II), Mg(II) and AI(III) ions was studied in aqueous solution using pH-potentiometric and UV-vis spectroscopic techniques. Al(III) ion was found to form more stable complexes with SalGiy than Ca(II) or Mg(II) ions. While AI(III) ion forms various 1:1 complexes of different protonation states in the pH range 2-7, Ca(II), Mg(II) ions seem to interact with SalGly only in the basic pH range and form mixed hydroxo species MLH_(-1) at pH ~ 8. According to the UV-vis spectroscopic measurements in the species MLH_(-1) the carboxylate-O^- atom and the phenolate-O^- coordinate to the metal ions. SalGly is able to keep Al(III) in solution through inner and outer sphere coordination to metastable amorphous AI(OH)_3 particles. Deprotonation of the peptide amide NH does not occur in these systems.
ISSN:1565-3633
1687-479X
DOI:10.1155/S1565363303000256