Patent ID: 7476726
Filing Date: 2009-01-13
Classification: C07K

Abstract:
1. A method of purifying endostatin protein comprising: (a) applying a sample comprising endostatin to a first cation exchange column, wherein the first cation exchange column is an expanded bed absorption column, and eluting a first eluate comprising the endostatin from the first cation exchange column using an elution buffer consisting essentially of 17 mM citric acid, 66 mM sodium phosphate, 250 mM NaCl, pH 6.3; (b) applying the first eluate comprising the endostatin to a heparin-sepharose column or to a column comprising a resin that selectively binds endostatin via a hydrophobic interaction mechanism and eluting a second eluate comprising the endostatin using an elution buffer consisting essentially of a mixture of 30% 20 mM Tris, 50 mM NaCl, pH 7.6 and 70% 20 mM Tris, 500 mM NaCl, pH 7.6; (c) applying the second eluate comprising the endostatin to an anion exchange column and collecting the flow-through comprising the endostatin; (d) applying the flow-through comprising the endostatin to a second cation exchange column and eluting a third eluate comprising the endostatin from the second cation exchange column using an elution buffer consisting essentially of 66 mM sodium phosphate 17 mM citric acid, 250 mM NaCl, pH 6.3; and (e) concentrating the endostatin.