Purification of human plasma α2 macroglobulin and α1 proteinase inhibitor using zinc chelate chromatography

Abstract

A method utilizing metal chelate chromatography has been developed for the large-scale purification of two major plasma proteinase inhibitors under nondenaturing conditions. α2 macroglobulin (α2M) and α1 proteinase inhibitor (α1PI) are both isolated from the same batch of pooled human plasma by (NH4)2SO4 precipitation and chromatography on zinc chelate columns. These two steps of the procedure result in the purification of α2 macroglobulin that is homogeneous as determined by polyacrylamide gel electrophoresis and immunoelectrophoresis. The α1 proteinase inhibitor requires two additional steps: chromatography on DE-52 cellulose at pH 6.5 and 7.5 to achieve homogeneity. Specific activities of the inhibitors are comparable to the highest previously reported.