Further Purification of a Chymotrypsin Inhibitor from Ascaris Lumbricoides and Its Reactions with Chymotrypsins Alpha and B.

Extracts of the body walls of Ascaris lumbricoides were reported by Green (2) to contain one substance capable of inhibiting chymotrypsin cy and another substance capable of inhibiting trypsin. Peanasky and Laskowski (3) separated these inhibitors by means of continuous paper curtain electrophoresis and crystallized the chymotrypsin inhibitor. The crystalline preparation, however, was heterogeneous by moving boundary electrophoresis. The present paper describes an improvement of the purification procedure by repeated molecular sieving alternately on Sephadex G-75 and Sephadex G-25. The preparation obtained is about 25% more active than the best crystalline preparations. It has constant specific activity across the peak and possesses only one NHz-terminal amino acid, arginine. It inhibits chymotrypsin a: (cationic chymotrypsin) and chymotrypsin B (anionic chymotrypsin) in the same manner.