Citrate Stabilization of Chromatographically Purified Factor VIII

When oxalated or resin-decalcified human plasma was adsorbed with barium sulfate, equilibrated with 0.0175M phosphate buffer (pH 6.3), and chromatographed through diethylaminoethyl (DEAE) cellulose, most of the plasma’s fibrinogen emerged from the column and factor XII was detected. No factor VIII was found. A second buffer phase, in which 0.04M phosphate buffer (pH 5.9) was used, removed more protein but not fibrinogen or factor VIII. A third phase, 0.10M phosphate buffer (pH 5.6), produced additional fibrinogen and, unlike the first fibrinogen fraction, factor XIII; but again, no factor VIII. A fourth and final phase, 0.40 to 0.50M phosphate buffer (pH 5.3), removed factors VIII and V, and the eluate contained no fibrinogen.

Although separation of fibrinogen into two components required the four-buffer system, maximal yields of factor VIII were achieved by compressing the first three buffer phases into one. Specific activities of about 50-fold, from large volumes of plasma, and 200-fold, from small volumes, were obtained.

Refined factor VIII was unstable unless citrate was added to a concentration of 0.4 per cent.