A　novel　lectin　with　a　molecular　mass　of　24.3 kDa,　designated　Lunatin,　was　isolated　from　edible　seeds　of　Phaseolus　lunatus　billb.　The　purification　scheme　consisted　of　ammonium　sulfate　precipitation,　affinity　chromatography,　ion　exchange　chromatography,　and　gel　filtration　chromatography.　The　lectin　is　a　glycoprotein,　as　determined　by　staining　with　periodic　acid-Schiff　(PAS),　and　its　N-terminal　amino　acid　sequence　was　determined　to　be　DAVIYRGPGDLHTGS.　Lunatin　exhibited　hemagglutinating　activity　towards　human　blood　group　A　erythrocytes,　which　was　mostly　preserved　up　to　50 °C　and　retained　at　ambient　temperature　at　pH　2.0–11.0.　D-fructose,　D-galactose,　D-glucose,　and　mannitol　were　capable　of　inhibiting　its　hemagglutinating　activity.　Lunatin　was　found　to　be　a　metal-dependent　protein,　as　its　activity　was　inhibited　by　the　metallic　compounds　K2Cr2O7,　SnCl2,　and　LiCl,　though　it　was　unaffected　by　MgCl2,　ZnCl2,　BaCl2,　CuCl2,　FeCl3,　or　CaCl2.　In　addition,　Lunatin　exerted　potent　antifungal　activity　toward　a　variety　of　fungal　species,　including　Sclerotium　rolfsii,　Physalospora　piricola,　Fusarium　oxysporum,　and　Botrytis　cinerea.　Finally,　proliferation　of　K562　leukemia　cells　was　strongly　inhibited　by　Lunatin,　with　an　IC50　of　13.7 μM,　whereas　HeLa　and　HepG2　cells　were　only　weakly　affected.　These　findings　further　the　identification　and　understanding　of　functional　factors　in　edible　plant　seeds.　©　2016　Elsevier　B.V.