Serine protease inhibitor which is active against trypsin. Displays strong antifungal activity against a number of phytopathogenic fungi including M.melonis, A.cucumerina, A.solani, C.glaeosporioides and P.capsici. Optimum pH is 8.0 at 37 degrees Celsius. Maintains over 90% of its inhibitory activity from pH 3 to 10. Active between 10 and 60 degrees Celsius. 84% activity retained when heated for 30 minutes at 80 degrees Celsius. Incubation at temperatures above 80 degrees Celsius rapidly decreases inhibitory activity. Belongs to the protease inhibitor I13 (potato type I serine protease inhibitor) family.