First report of an antifungal amidase from Peltophorum ptercoarpum

A 60 kDa antifungal amidase was purified from Peltophorum ptercoarpum seeds using an isolation procedure that entailed ion‐exchange chromatography on Q‐Sepharose, ion‐exchange chromatography on DEAE‐cellulose and FPLC–gel filtration on Superdex 75. Unlike most other antifungal proteins isolated previously, it was adsorbed on Q‐Sepharose and DEAE‐cellulose. The isolated protein, designated as peltopterin, exhibited an N‐terminal amino acid sequence closely resembling those of amidases. It exhibited amidase activity and digested iodoacetamide with an optimum pH and temperature at pH 9 and 50°C, respectively. It also hydrolyzed acrylamide and urea. It impeded mycelial growth in Rhizotonia solani with an IC₅₀ of 0.65 μm . Chitin deposition at hyphal tips in R. solani was observed by staining with Congo red after incubation with peltopterin. Its antifungal activity was stable throughout pH 0–14 and 25–100°C. It potently inhibited HIV‐1 reverse transcriptase with an IC₅₀ of 27 nm . Copyright © 2009 John Wiley & Sons, Ltd.