Isolation and characterization of a 27-kDa antifungal protein from the fruits of Diospyros texana.

We have purified a 27 kDa protein from the overripe fruits of Diospyros texana to homogeneity by ammonium sulfate precipitation, DEAE-Sepharose and C18 reversed phase column chromatographies. The purified protein inhibited the growth of the agronomically important pathogen Phytophthora infestans, the causative agent of potato late blight. Sequence analysis of the purified protein indicated that it has significant homology to thaumatin and other reported thaumatin-like antifungal proteins.