The acid-dialyzed sample was centrifuged at 14,000 x g for 30 min at 4 °C and the CP-enriched supernatant (acid-SN) loaded on a carboxy methyl-Sepharose (CM-Sepharose) column pre-equilibrated with 100 mM Na-acetate/acetic acid buffer pH 5.0 containing 1 mM EDTA