diagrams – Ypatent

The method of almost universal choice for large scale operation is “method 6” as described by Cohn. Briefly, in 1) crude fibrinogen is removed by centriguation from plasma by adding cold 53.3% ETOH to a final concentraiton of 8% ETOH, temp -2.5-3. 2) 53.3% ETOH is added to the supernatant to attain a concentraiton of about 25% ETOH, temp about ‘5 and pH about 6.9. The resulting precipitate (Fraction II+III) contains the immune globulins and other proteins which is removed by centrifugation at about -5. (3) a fraction consisting of most of the alpha globulins (and called IV-1) is precipitated by adding water to the 25% ETOH supernatant until a concentration of about 18% ETOH is reached, and the pH is adjusted to about 5.3, temp about -5. Fraction IV-1 is removed by centrifugation. (4) the ETOH concentraiton of the 18% ethanol supernatant is increased to 40 and pH adjusted to about 5.9. Under these conditions, another fraciton (IV-4) is precipitated and removed by centrifugation. (5) the 40% ETOH supernatant is clarified by UF at -5C and the albumin fraction precipitated therefrom by adjustment of the pH to 4.8 (with acetic acid-sodium acetate buffer). The precipitated albumin fraction is then removedd by centrifugation and further purified by dissolving in 10% ETOH and reprecipitating by adjusting the ETOH to about 40% at pH of 5.2. from Tillman (US2,710,294)

method6