Separation of kininogens by gel filtration of plasminogen-free human plasma.

Abstract

Abstract High molecular weight kininogen (S1) is useful as a sensitive substrate in assays of the kininogenase activity of plasma kallikrein, but considerable difficulties are encountered in the isolation of this kininogen due to loss by “spontaneous” activation. In the present work a satisfactory yield (40–60 %) of a crude preparation of S1 was obtained through gel chromatography on Sephadex G–200 of plasminogen–free 60°‐heated human citrated plasma. Low molecular weight kininogen (S2) was also obtained by the same procedure. The two kininogen preparations did not contain significant amounts of inhibitors of human plasma kallikrein, hog pancreas kallikrein or human plasmin, as judged by the stability of the arginyl–esterase activities of these enzymes in contact with the kininogens. Both S1 and S2 were stable for at least one year when stored at ‐20°. A preparation of human plasma kallikrein reacted specifically with S1, while both hog pancreas kallikrein and human plasmin also reacted with S2. The quantitative data are in accordance with the assumption that hog pancreas kallikrein and plasmin release bradykinin from S1 and kallidin from S2. The rate of release of kinin produced by hog pancreas kallikrein in S2 occurred twice as fast as in S1, while the opposite was registered for plasmin.