Use of Heparin in Distinguishing Plasma Kallikrein from Pf/dil

Summary The ability of heparin to inhibit both kallikrein and Pf/dil was demonstrated. Since about 6 times as much heparin was required to inhibit kallikrein as Pf/dil, it was possible to determine the amount of each in an unknown solution from the per cent inhibition produced by a given amount of heparin. Using this method, the nature of the permeability activity of diluted serum was investigated and found to be caused solely by Pf/dil.