Background and objectives: Because the current demand for alpha-1-protease inhibitor (A1PI) exceeds the available supply, we aimed to develop a process for purification of A1PI from plasma which would achieve the highest possible degree of purity, specific activity and yield.
Materials and methods: A1PI was purified from Cohn fraction IV-1,4 using ethanol precipitation and Q-Sepharose chromatography. Ceramic hydroxyapatite chromatography was used as a final purification step. Two independent virus-inactivation procedures (chemical and vapour heating) were applied.
Results: The resulting A1PI had an unprecedented high specific activity. In addition, the process led to the discovery of a new isoform of A1PI in isoelectric focusing gels.
Conclusion: The high specific activity of the A1PI preparation achieved with this process should allow a reduction of the A1PI total protein load necessary to achieve clinically relevant effects.