Purification and characterization of human caseinomacropeptide produced by a recombinant Saccharomyces cerevisiae

Caseinomacropeptide (CMP) is a biologically active polypeptide derived from the C-terminal of milk κ-casein. CMP is heterogeneous since it is modified differently by glycosylation and phosphorylation after translation. Recently, recombinant human CMP (hCMP) has been produced as a secretory product in yeast. The present study aimed at the purification and characterization of recombinant hCMP. By sequential molecular cut-off ultrafiltration and anion-exchange chromatography, the recombinant hCMP in the culture broth could be purified to an HPLC purity over 94%. The authenticity of the purified hCMP was confirmed by sequence analysis of N-terminal amino acids. The recombinant hCMP was estimated to be 7.0 kDa by SDS-PAGE, and showed a lower glycosylation than the natural bovine CMP.