Purification and characterization of a chitinase-like antifungal protein from black turtle bean with stimulatory effect on nitric oxide production by macrophages.
An antifungal protein was isolated from black turtle bean, Phaseolus vulgaris cv. "Black Turtle". The purified protein displayed an N-terminal amino acid sequence with 60-80% homology to chitinases. The isolated protein specifically inhibited two species of fungi, namely Fusarium oxysporum and Mycosphaerella arachidicola , among several phytopathogenic fungi tested. Its antifungal activity was retained after incubation at 60 degrees C for 15 minutes, diminished after exposure to 80 degrees C, and was completely abrogated after treatment at 100 degrees C. The antifungal protein had higher thermostability than the antifungal protein mollisin from chestnut. It stimulated nitric oxide production by murine peritoneal macrophages, but exerted neither mitogenic nor cytotoxic activity on murine splenocytes, activities that may be related to allergic responses.
Chu
Kin Tak
KT
Department of Biochemistry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, PR China.
Ng
Tzi Bun
TB
D000595:Amino Acid Sequence; D000818:Animals; D000935:Antifungal Agents / Q000037:antagonists & inhibitors / Q000302:isolation & purification* / Q000494:pharmacology*; D002688:Chitinases / Q000737:chemistry; D003907:Dexamethasone / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000096:biosynthesis*; D027805:Phaseolus / Q000737:chemistry*
D000935:Antifungal Agents; D009569:Nitric Oxide; D003907:Dexamethasone; D002688:Chitinases; D019331:NG-Nitroarginine Methyl Ester