A Chymotrypsin Inhibitor From the Parasitic Nematode, Oesophagostomum radiatum

Abstract

An inhibitor of oc-chymotrypsin was isolated from O. radiatum by affinity chromatography, as well as by ion-exchange and molecular sieve chromatography. The inhibitor was associated with the cuticle or musculature of the parasite. It completely inhibited the esterolytic activity of chymotrypsin. Molecular sieve chromatography gave an apparent molecular weight of 9700 for the inhibitor alone and 32000 for the complex with chymotrypsin. This suggests reaction in a 1: 1 molar ratio. The inhibitor reacted with diisopropyl phosphoryl-chymotrypsin weakly, if at all.