Patent ID: 7879800

Claim:
A large scale process for purifying alpha-1 proteinase inhibitor (API) from an unpurified mixture of proteins comprising: (a) dispersing the unpurified mixture of proteins containing API in an aqueous medium; (b) removing a portion of contaminating lipids and proteins by adding a lipid removal agent to the aqueous dispersion and precipitating the portion of contaminating proteins from said aqueous dispersion; (c) loading an API-containing supernatant of step (b) containing API on a first anion exchange resin with a buffer solution having pH and conductivity such that API is retained on the first anion exchange resin; (d) eluting an API-containing fraction from said first anion exchange resin with a same type of buffer as in step (c) having adjusted pH and conductivity; (e) loading an API-containing fraction of step (d) on a cation exchange resin in said same type of buffer having appropriate pH and conductivity such that API is not retained on the cation exchange resin; (f) collecting a flow-through of step (e) that contains API; (g) loading an API-containing fraction of step (f) on a second anion exchange resin with said same type of buffer having appropriate pH and conductivity such that API binds to the second anion exchange resin; and (h) eluting API from said second anion exchange resin with said same type of buffer having adjusted pH and conductivity to obtain a purified active API which is stable without the addition of a protein stabilizer.