The present invention provides a process suitable for processing scaled-upamounts of source material in the range of tens of kilograms for thepurification of alpha-1 proteinase inhibitor (API) from a mixture ofunpurified proteins. More particularly, the present invention relates to aprocess for the purification of API from blood plasma or from plasma fractionsto obtain pharmaceutical grade API on a commercial scale. The API produced bythe process of the present invention is highly pure (at least 90% API out ofthe total protein) and highly active (at least 90% active API). The presentinvention also relates to pharmaceutical compositions comprising the purifiedAPI and methods of using same.
