Figure 2. Determination of IC₅₀ and Ki for a trypsin inhibitor purified from seeds of Erythrina velutina (EvTI).

A. Inhibition curve of trypsin. IC₅₀ was determined as EvTI concentration which inhibits 50% of trypsin activity. B. The inhibition constant (Ki) of EvTI on trypsin was determined by the method of Dixon (1979).