Studies on the purification of antihemophilic factor (factor 8. I. Precipitation of antihemophilic factor by concanavalin A.

Concanavalin A precipitates antihemophilic factor from normal plasma. Combining this precipitation with other techniques, we were able to separate fractions rich in antihemophilic activity from human plasma with rapidity. The molecular weight of antihemophilic factor was estimated to be greater than 2 million. Presumably, antihemophilic factor is a large glycoprotein.