RÉSUMÉ
An inhibitor of trypsin and chymotrypsin was purified from horse gram (Dolichos biflorus) beans. The concentration of the inhibitor which provided total inhibition was 0.27 μg/μg tryptic enzyme and 0.46 μg/μg chymotryptic enzyme. The inhibitor was stable at 37°C between pH of 3 to 11 and at 97°C, upto pH 5.0 only. While the activities were rapidly lost in 0.1Ν NaO H the loss was only 5 0% in 0.1Ν HCl when kept for 2 h at 97°C. On heating at pH 7.8, it remained stable upto 80°C with a gradual loss in activities at 97°C and a total loss occurring by autoclaving at 15 psi for 10 min. Reduction of disulphide bonds by 2-mercaptoethanol, pronase digestion and boiling in the presence of 1 Μ NaCl led to reduction in the activities. However, the inhibitor was resistant to the action of pepsin and subtilisin and to urea at 37°C.