A process for purifying the proteinase alpha-1 inhibitor (IPA) from an unpurified protein mixture comprising: a. dispersion of the unpurified protein mixture containing the IPA in an aqueous medium； b. removal of a portion of the lipids and contaminating proteins by adding silicon dioxide to the aqueous dispersion as a lipid removal agent and precipitation of the portion of contaminating proteins from said aqueous dispersion by adding polyalkylene glycol； C. loading of the supernatant containing IPA from step (b) in a first anion exchange resin with a buffer solution having a pH and conductivity such that the IPA is retained in the first anion exchange resin； d. elution of a fraction containing IPA of said first anion exchange resin with the same type of buffer as in step (c) having adjusted the pH and conductivity； and. loading of the fraction containing IPA from step (d) in a cation exchange resin in said same type of buffer having an appropriate pH and conductivity such that the IPA is not retained in the cation exchange resin； F. collection of the flow through step (e) containing IPA； g. loading the fraction containing IPA from step (f) into a second anion exchange resin with said same type of buffer having an appropriate pH and conductivity such that the IPA binds to the second anion exchange resin； h. elution of the IPA of said second anion exchange resin with said same type of buffer having adjusted the pH and conductivity to obtain a solution containing active and purified IPA.Un proceso para purificar el inhibidor de proteinasa alfa-1 (IPA) a partir de una mezcla no purificada de proteínas que comprende: a. dispersión de la mezcla no purificada de proteínas que contiene el IPA en un medio acuoso； b. eliminación de una porción de los lípidos y proteínas contaminantes añadiendo a la dispersión acuosa dióxido de silicio como un agente de eliminación de lípidos y la precipitación de la porción de proteínas contaminantes de dicha dispersión acuosa añadiendo poli
