2 10 mM KPi, 0.1 M NaCl, pH 7.0 5 buffer (37 ml) to buffer + 0.5 M K phosphate (37 ml) hydroxyapatite column chromatography (Bio-Rad Laboratories, CHT5-I) 7 0.11 M K phosphate Column chromatography 2 _ crib220u270rib220u49433i