The Relationship between PF/DIL and Activated Human Hageman Factor

Abstract Permeability factor of dilution (PF/dil) activity, prepared by dilution of human plasma in contact with glass, was removed by insolubilized antibody to human Hageman factor. Insolubilized normal globulin or antibodies to prekallikrein failed to remove PF/dil activity. Dilutions of Fletcher trait plasma (a prekallikrein deficiency) failed to generate PF/dil activity but addition of purified prekallikrein reconstituted the capacity to generate PF/dil activity. These data support the conclusion that PF/dil and activated Hageman factor are identical and that generation of PF/dil (HFa) requires fluid phase activation with kallikrein.</jats:p

Structural Changes Accompanying Enzymatic Activation of Human Hageman Factor

The structure of Hageman factor, isolated from human plasma, was analyzed before and after enzymatic activation. The purified molecule is a single polypeptide chain of 80,000 molecular weight (mol wt) sedimenting at 4.5S. An amino acid analysis has been performed. The concentration of Hageman factor in normal human plasma was found to be 29 μg/ml with variation between individuals ranging from 15 to 47 μg/ml. Treatment of the molecule with kallikrein, plasmin, or trypsin resulted in cleavage at two primary sites, yielding fragments of 52,000, 40,000, and 28,000 mol wt. No further changes occurred in the fragments with subsequent reduction. Prekallikrein-activating ability was associated exclusively with the 28,000 moiety