Might act as a protease inhibitor involved in plant defense responses. Expressed in roots, leaves, epidermal layers of elongating stems, meristems and in the vascular system. Belongs to the protease inhibitor I3 (leguminous Kunitz-type inhibitor) family. Was originally thought to be an alpha-L-fucosidase. The nucleotide sequence (X82595) deposited at the EMBL differs from that shown in PubMed:7559605 with the same accession number.