Synthesis of a new chelating gel: removal of Ca2+ ions from parvalbumin.

The synthesis of a chelating gel which contains the effective metal chelating agent ethylenediaminetetraacetic acid covalently linked to amino-agarose is described. This gel is shown to be a rapid and extremely effective material for the removal of tightly bound, but labile metal ions from proteins without introducing contaminants into the biological system. The synthesis involves the formation of an amide linkage between the dangling carboxylate arm of the [Co(EDTA)Cl]2-complex and amino-agarose using a standard carbodiimide coupling reaction. The chelating gel is shown to remove approximately 98.5% of the calcium from fully bound Ca2-parvalbumin and over 99% of the europium from Eu2-parvalbumin.