The diseaseFusarium head blight (scab) causes severe problems for farmers and for the industries that use cereals. It is likely that the fungi that cause scab (Fusariumspp.) use various enzymes when they invade grains. We are studying enzymes that the fungi may use to hydrolyze grain proteins. To do this,Fusarium culmorumwas grown in a gluten-con-taining medium from which an alkaline serine proteinase with a molecular mass of kDa was puri®ed by size-exclusion and cation exchange chromatographies