CYSTEINE PROTEASE INHIBITOR FROM PEARL-MILLET - A NEW CLASS OF ANTIFUNGAL PROTEIN

A Cysteine protease inhibitor exhibiting antifungal activity from pear l millet seeds has been purified to homogeneity by ammonium sulphate p recipitation and chromatographic procedures involving CM-sephadex and SP-sepharose cation exchange columns. The molecular characterization h as revealed its molecular mass as 24 kD and isoelectric point 9.8. The amino acid composition data shows presence of high content of serine and glycine (34 residues / mole) and absence of tryptophan. The inhibi tor exhibits potent antifungal activity against Trichoderma reesei, a dead mood fungus with minimum inhibitory dose to inhibit mycelial grow th or spore germination is as low as 1 mu g / ml (250 ng/disc). in add ition to Trichoderma reesei, the antifungal activity is observed again st some important phytopathogenic fungi, namely, Claviceps, Helminthos porium, Curvularia, Alternaria and Fusarium species. To the best of ou r knowledge, a cysteine protease inhibitor as an antifungal protein is reported for the first time from a plant system. (C) 1998 Academic Pr ess.