Recombinant human follicle stimulating hormone purification by a short peptide affinity chromatography

Peptide KVPLITVSKAK was selected to design a synthetic ligand for affinity chromatography purification of recombinant human follicle stimulating hormone (rhFSH), based on the interaction of the hormone with the exoloop 3 of its receptor. The peptide was acetylated to improve its stability to degradation by exopeptidases. A cysteine was incorporated at the C-termini to facilitate its immobilization to the chromatographic activated SulfoLink agarose resin. A sample of crude rhFSH was loaded to the affinity column, using 20 mM sodium phosphate, 0.5 mM methionine, and pH 5.6 and 7.2 as adsorption and elution buffers, respectively. The dynamic capacity of the matrix was 54.6 mg rhFSH/mL matrix and the purity 94%. The percentage of oxidized rhFSH was 3.4%, and that of the free subunits was 1.2%, both in the range established by the European Pharmacopeia, as also were the sialic acid content and the isoforms profile.