An　isolation　procedure　comprising　affinity　chromatography　on　Affi-gel　blue　gel,　ion　exchange　chromatography　on　SP-Toyopearl,　and　fast　protein　liquid　chromatography　on　Mono　S　was　used　to　purify　a　peptide　from　broad　beans　which　manifested　antifungal　activity　toward　Mycosphaerella　arachidicola,　Fusarium　oxysporum,　and　Botrytis　cinerea.　The　peptide　demonstrated　a　molecular　mass　of　7.5　kDa.　N-terminal　sequence　analysis　disclosed　the　identity　of　the　antifungal　peptide　to　be　a　trypsin-chymotrypsin　inhibitor.　The　trypsin-chymotrypsin　inhibitor　also　exerted　an　inhibitory　action　on　chymotrypsin　activity　and　HIV-1　reverse　transcriptase　activity.　Proliferation　of　murine　splenocytes　was　stimulated　in　the　presence　of　the　trypsin-chymotrypsin　inhibitor.　This　report　constitutes　the　first　observation　of　antifungal　activity　of　a　leguminous　peptidic　protease　inhibitor.　©　2001　Academic　Press.