Column chromatography buffer (60 ml) to buffer + 0.5 M NaCl (60 ml) 0.4 M NaCl crib220u270rib220u36162i 30 _ 3 9 20 mM Tris-HCl, pH 8.0 4 anion exchange column chromatography (TOSOH CORPORATION, Super Q TOYOPEARL 650M)