A Pre-Albumin Activator of Prekallikrein

Abstract

Chromatography of human serum on diethylaminoethyl cellulose reveals five peaks having bradykinin-generating activity. Kallikrein is found in peak 1, Hageman factor is found overlapping peaks 2 and 3, and a prekallikrein activator is found in peaks 2 through 5. Further purification of the prekallikrein activator by gel filtration, carboxymethyl cellulose chromatography, and elution from unstained sliced disc gels after electrophoresis gave purified material which appeared heterogeneous and had an estimated molecular weight of 30,000 to 40,000. Throughout each step of purification, the prekallikrein activator retained the ability to correct specifically the coagulation defect of Hageman factor deficiency. Prolonged dialysis of a partially purified preparation of active Hageman factor resulted in the development of pre-albumin bands in the position previously noted for the highly purified prekallikrein activator. The development of these bands and their associated clot-promoting and prekallikrein-activating abilities at low ionic strength and the prevention of these events at high ionic strength but under otherwise identical conditions are consistent with the direct derivation of the low molecular weight pre-albumin prekallikrein activator from active Hageman factor.