Purification of Alpha 1 Proteinase Inhibitor from Human Plasma Fraction IV-1 by Ion Exchange Chromatography.

BACKGROUND AND OBJECTIVES:Alpha-proteinase inhibitor (PI) protects the lungs from proteolytic damage caused by elastase and can be used to treat congenital emphysema. We describe an improved method of purification of alpha 1 PI from redissolved fraction IV-1 paste.MATERIALS AND METHODS:The process used dimethylaminoethyl anion exchange chromatography, 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 loading conditions for ion exchange chromatography at small scale (20-60 ml of suspension) are described. Virus inactivation was adjusted to provide the best yield of alpha 1 PI consistent with effective inactivation. The process has been effectively scaled up.RESULTS:The final product was approximately 90% pure by SDS-PAGE, with a 60-70% yield from starting fraction IV-1 paste. The process has been characterized by methods including nonreduced SDS-PAGE, alpha 1 PI inhibition assay, and biuret protein assay.CONCLUSION:The method described is an effective way of preparing large quantities of alpha 1 PI from fractionated plasma.