A study of strontium binding to albumins, by a chromatographic method involving atomic emission spectrometric detection

A chromatographic method involving ICP-AES (inductively coupled plasma atom ic emission spectrometry) detection has been successfully applied for the s tudy of strontium-protein complexes. The chromatographic step involves the use of gel filtration-a large-tone Hummel and Dreyer method-which allows to dissociate the bound metallic ions and the free ones. This step is followe d by an ICP-AES analysis of fractions collected throughout the chromatograp hic experiment: the concentration of ionic metallic species in solution can therefore be calculated. Two proteins have been tested: bovine serum album in, which showed only weak interactions with Sr2+ ions, and bovine cc-lacta lbumin: this protein, well-known for its calcium binding capacity, proved t o interact strongly with strontium. The influence of various parameters on the formation of strontium-lactalbumin complexes were determined, namely te mperature, pH. Competition experiments between Sr2+ ions and, respectively Na+ and Ca2+ ions were also performed, by varying ionic strength of the med ium, and by using both apo and native forms of bovine a-lactalbumin. (C) 19 99 Elsevier Science B.V. All rights reserved.