In Vivo Interaction between α-Chymotrypsin and Plasma Proteins in the Dog

Minute amounts of bovine 125I-α-chymotrypsin injected intravenously into the dog were bound to the α1-antitrypsin (about 85 per cent) and the a-macroglobulins (about 15 per cent). Injection of larger amounts resulted in a fall of the concentration of the α-macroglobulins. Chymotrypsin-α-macroglobulin complexes were rapidly eliminated from the blood stream. There was a transfer of chymotrypsin from chymotrypsin-α1-antitrypsin complexes to both α-macroglobulins. The dogs did not show any signs of a general reaction before the α1-antitrypsin had been saturated with chymotrypsin. There was then a tendency to shock and hypercoagulability followed by fibrinolysis and death. It is concluded that α-antitrypsin is a stronger inhibitor of chymotrypsin than of trypsin.