A novel human leukocyte elastase inhibitor from duck egg white

A serine proteinase inhibitor (ovomucoid) has been isolated from duck egg white. The duck ovomucoid effectively inhibited HLE, PPE, chymotrypsin, and HCG in a 1:1 molar ratio, and trypsin in a 1:2 molar ratio. Inhibition of human plasmin and porcine pancreatic kallikrein was not observed. The ovomucoid shows equilibrium dissociation constants of 0.002; 2.4; 2.2; 6.1; and 18.0 nhl for HLE, PPE, chymotrypsin, trypsin, and HCG, respectively. The molecule of inhibitor can simultaneously bind two trypsin molecules and one molecule of elastase (or chymotrypsin).