Fibrinogenolytic Demonstration of Activation and Inhibition of Tryptase in Plasma Protein Fraction-I (“Antihemophilic Globulin”). ∗

Abstract

Summary

The present study is based upon the use of a fibrinogenolytic (rather than fibrinolytic) technic for demonstration of a natural plasma protease (tryptase) and its precursor (tryptogen) in the fibrinogen-rich plasma fractions. The value of streptokinase (miscalled “streptococcal fibrinolysin”) for activation of the enzyme precursor is confirmed and tests are presented to show that failure to secure proteolytic effects e.g. in bovine plasma Fraction I, is due to lack of tryptogen (tryptase precursor) rather than to any significant presence of tryptase-in-hibitor.

Heparin, unaided, shows no enzyme-inhibitory effects in the cited tests. Antitryptase effects of (a) crystalline inhibitors, from pancreas and soybean, and (b) crude and fractionated egg-albumen, favor the characterization of the plasma protease as a “tryptase.”

Confirmation of the existence of tryptogen, together with a trace of active tryptase, in H.F. (“antihemophilic globulin”) is further, but still inconclusive, evidence that the source of the coagulation defect in hemophilia is to be sought for in the complexities of the plasma protease system.