PURIFICATION OF ALPHA(1) PROTEINASE-INHIBITOR FROM HUMAN PLASMA FRACTION IV-1 BY ION-EXCHANGE CHROMATOGRAPHY

Background and Objectives: alpha-proteinase inhibitor (PI) protects th e lungs from proteolytic damage caused by elastase and can be used to treat congenital emphysema. We describe an improved method of purifica tion of alpha(1) PI from redissolved fraction IV-1 paste. Materials an d Methods: The process used dimethylaminoethyl anion exchange chromato graphy, sulfopropyl cation exchange chromatography, virus inactivation by dry heat, and tri-n-butyl-phosphate/cholate treatment, followed by a second strong cation exchange chromatography. Optimizations of load ing conditions for ion exchange chromatography at small scale (20-60 m l of suspension) are described. Virus inactivation was adjusted to pro vide the best yield of alpha(1) PI consistent with effective inactivat ion. The process has been effectively scaled up. Results: The final pr oduct was approximately 90% pure by SDS-PAGE, with a 60-70% yield from starting fraction IV-1 paste. The process has been characterized by m ethods including nonreduced SDS-PAGE, alpha(1) PI inhibition assay, an d biuret protein assay. Conclusion: The method described is an effecti ve way of preparing large quantities of alpha(1) PI from fractionated plasma.