Human plasma kallikrein: purification, enzyme characterization and quantitative determination in plasma.
Human plasma kallikrein was isolated from a plasma fraction related to Cohn fraction IV4 by affinity- and Sephadex G-150 chromotography yielding a material with 17.3 TAME-U/A280 unit. The preparation was characterized by immunological and enzymatic methods. Complex formation with alpha2-macroglobulin, C1-inactivator and aprotinin was demonstrated by immunoelectrophoresis. The bradykinin release from high-molecular weight kininogen and its inhibition by antibodies to kallikrein, AT III and AT III-heparin complex were measured using a biological test system (rat uterus). Time dependent inactivation of kallikrein by AT III, and AT III-heparin complex was shown by means of a synthetic kallikrein substrate: Bz-Pro-Phe-Arg-pNan. The same substrate was used to measure the activation of prekallikrein in plasma by kaolin and F XII a. Antibodies raised against kallikrein were shown to inhibit the reaction specifically. A quantitative determination of plasma prekallikrein by electroimmunodiffusion according to Laurell was developed: the plasma concentration in normal individuals was found to be 1.8 - 2.2 TAME-U/ml related to kallikrein activity; this corresponds approximately to 9 - 11 mg antigen/100 ml plasma.
D000818:Animals; D001681:Biological Assay; D001920:Bradykinin; D005260:Female; D006801:Humans; D005779:Immunodiffusion; D007122:Immunoelectrophoresis; D007074:Immunoglobulin G; D007610:Kallikreins / Q000097:blood* / Q000302:isolation & purification; D008970:Molecular Weight; D051381:Rats; D014599:Uterus
D007074:Immunoglobulin G; D007610:Kallikreins; D001920:Bradykinin