Designing a new manufacturing processes for plasma proteins to maximise alpha-1 antitrypsin recovery
The majority of plasma fractionators use ethanol fractionation to manufacture proteins. The ethanol denatures some proteins and alpha-1 antitrypsin is one of them. Knowledge of the proteins present in fractions from the Kistler and Nitschmann process alongside chromatographic choices, has led us to design an efficient process for the manufacture of alpha-1 antitrypsin (AAT). AAT, a major inhibitor of proteases has been purified from A+1 supernatant using a three step chromatographic process. The A+1 supernatant was loaded to copper charged chelating sepharose at pH 6.2 and 2.5 mM imidazole where at least 99.5% of albumin and alpha-1 acid glycoprotein (AAG) flowed through and AAT, transferrin (Tf) and haptoglobin (Hp) were bound. The eluate from this column was loaded to a Ni sepharose 6 fast flow column, stripped of its nickel ions and charged with copper ions (pH 6.2 and 2.5 mM imidazole). The AAT does not bind under these conditions whilst the transferrin and haptoglobin do. The AAT was further purified on anion exchange to yield a product that was at least 80% pure and 100% active. Currently albumin is manufactured using two more ethanol fractionation steps and an anion exchange column. We describe a method where albumin and AAG are efficiently separated using diiethylamino ethoxy (DEAE) sepharose at pH 4.6. These two chromatographic steps yield albumin of comparable purity to that manufactured by the ethanol fractionation process. We further propose a method of separating Hp and Tf using an anion exchanger; thus completing the processing of all the important proteins found in A+1 supernatant.
Journal: Food and Bioproducts Processing - Volume 86, Issue 1, March 2008, Pages 65–73