Inhibitor of fungal polygalacturonase. It is an important factor for plant resistance to phytopathogenic fungi. Inhibits all polygalacturonases (PG) tested, with the exception of PG from F.oxysporum which was only inhibited at 60%. Asn-303 is not glycosylated. Belongs to the polygalacturonase-inhibiting protein family. It is uncertain whether Met-1 or Met-10 is the initiator.