Mechanistic model for adsorption of immunoglobulin on hydroxyapatite

A model is developed for correlating the adsorption of protein to hydroxyapatite in terms of pH, phosphate and imidazole. It provides a basis for manipulating the chromatography conditions so as to obtain the best possible fractionation. The adsorption mechanism is apparently a function of two calcium affinity interactions and cation exchange. We used immunoglobulins and a fusion protein with or without a poly(6)histidine tag for our investigation. The results are presented and discussed in the present study.