A rapid method for the isolation of coagulation factor XII from human plasma

Zinc chelate affinity chromatography was used to develop a rapid, three-step procedure to isolate coagulation factor XII from human plasma. The first step was ammonium sulphate fractionction which gave a 2-fold purification and 90% recovery in the 25–50% saturation fraction. The second step was zinc chelate affinity chromatography which gave a 240-fold purification and 67.5% recovery. The third step was zinc chelate affinity chromatography again, but with the application of a pH gradient. The overall recovery of zymogen factor XII was 21.7% and the total purification was 1992-fold. The purified factor XII had an apparent molecular weight of 77 600 as determined by SDS-polyacrylamide gel electrophoresis and a specific activity of 50 units/mg on a clotting assay.