Interaction of lanthanide ions with glutamic acid and γ-carboxyglutamic acid

Abstract

Interactions of lanthanide ions with glutamic acid and γ-carboxyglutamic acid has been studied by the NMR method. These investigations made it possible to determine the coordination mode of aminoacids with lanthanide ions. The results are also of biological interest, since the lanthanides are often used as probes in calcium biochemistry. From our earlier studies on interaction of La(III), Lu(III) and Nd(III) ions with aspartic acid and asparagine it follows that light and heavy lanthanide ions interact in different ways with the carboxylic groups of aminoacids. In order to confirm this suggestion we extended our studies to glutamic acid and γ-carboxyglutamic acid. 1H, 13C NMR and electron spectra were recorded. Correlation of NMR chemical shifts with hypersensitive band intensity changes of lanthanide ions allows the determination of the coordination mode of the discussed aminoacids. Obtained results were confirmed by the Eu(III) luminescence spectra.