Alocasin, an anti-fungal protein from rhizomes of the giant taro Alocasia macrorrhiza

Abstract

An anti-fungal protein designated alocasin was isolated from the rhizomes of the giant taro Alocasia macrorrhiza. The isolation protocol involved ion exchange chromatography on diethylaminoethyl (DEAE)–cellulose, ion exchange chromatography on sulfopropyl (SP)–Sepharose, and gel filtration on Superdex 75. Alocasin, which was unadsorbed on DEAE–cellulose and SP–Sepharose, possessed the N-terminal sequence APEGEV, which exhibited some similarity to that of the miraculin-like anti-fungal protein from Pisum sativum legumes. It demonstrated a molecular mass of 11 kDa in sodium dodecyl sulfate–polyacrylamide gel electrophoresis and gel filtration, and displayed anti-fungal activity against Botrytis cinerea. Alocasin reduced the activity of HIV-1 reverse transcriptase. It exhibited weak hemagglutinating activity, only at a concentration of 1 mg/ml.