Finally utilizing selective titrations, counter current chromatography and reverse phase chromatography the elements are separated from each other and converted into oxides, hydroxides, salts and organometallic compounds.

The protein is then desalted and concentrated on a reverse phase chromatography column, preferably a POROS R/M reverse phase chromatography column, and thereafter lyophilized.

Illustratively, recombinant EPO is isolated from culture fluids by reverse phase chromatography employing a C4 or C6 column and elution with ethanol.

A partially purified active extract from the protein-rich fraction has been identified, using ion-exchange chromatography, reversed-phased chromatography, adsorption chromatography and gel filtration.