Inhibits bovine, insect and wheat chymotrypsins. Inhibits bovine chymotrypsin with Ki of 0.6 nM. Does not inhibit human or wheat alpha-amylases, bovine pancreatic trypsin, or trypsin-like activity isolated from wheat. Optimum pH range is 7.0-9.0. Optimum temperature is 25 degrees Celsius. Belongs to the protease inhibitor I6 (cereal trypsin/alpha-amylase inhibitor) family.