Isolation and characterization of a prealbumin activator of prekallikrein from acetone-activated human plasma

Abstract

A prealbumin activator of prekallikrein was isolated from acetone-activated human plasma by preparative disc gel electrophoresis in 15% polyacrylamide. The purification factor was 70, and the recovery was 20–30%. The purified preparation was functionally free of factors II, IX, and X, and it did not clot fibrinogen. It had a weak BAEe esterase activity, but was inactive towards kininogen, fibrin, and plasminogen. C1-inactivator, α 2-macroglobulin, and α 1-mantitrypsin could not be demonstrated by immunochemical techniques. The preparation was homogeneous on disc gel electrophoresis. The prekallikrein activator in the preparation had an estimated molecular weight of 32,000, and the isoelectric point was 4.2. The preparation also activated plasminogen proactivator and the proenzyme form of factor XI. It is concluded that the preparation contained factor XII f, and that preparative polyacrylamide disc gel electrophoresis of acetone-activated plasma may represent a simple method for the purification of factor XII f.