A study on antifungal proteins, ribonucleases and hemagglutinins, examples of defense proteins.

摘要

Defense proteins are ubiquitously found in all kinds of organisms to protect themselves from foreign pathogenic attacks. In the present study, three kinds of defense proteins, including antifungal proteins, a ribonuclease (RNase) and hemagglutinins have been isolated with an array of chromatographic methods. Ion exchange chromatography, affinity chromatography and gel filtration were applied to isolate these defense proteins. Physical and biological properties of these proteins were examined.;An antifungal protein, named actinchinin, has been isolated from green kiwi fruits (Actinidia chinensis Planchon cv. 'Gold Flesh'). Actininchin is 25 kDa in molecular mass. It inhibits the growth of the fungus Fusarium oxysporum with an IC50 of 7.5 muM.;Alliumin, an antifungal protein, has been purified from multiple-cloved garlic bulbs. Alliumin inhibits the growth of the fungus Mycosphaerella arachidicola with an IC50 of 1.3 muM. It can also inhibit the growth of bacterium Pseudomonas fluorescens.;A ribonuclease (RNase) is obtained from the brown oyster mushroom. The RNase exhibits the highest activity toward poly A, lower activity toward poly C, slight activity toward poly G, and indiscernible activity toward poly U.;A hemagglutinin, PVA, is purified from the flageolet beans ( Phaseolus vulgaris cv. 'Flageolet Bean').;A 67-kDa hemagglutin named SRA is isolated from the small red kidney beans (Phaseseolus vulgaris cv. 'Small Red Kidney Bean'). SRA exhibits neither antifungal activity toward fungi Botrytis cinerea, Fusarium oxysporum and Mycosphaerella arachidicola nor mitogenic activity toward murine splenocytes.;DRA, a 67-kDa hemagglutinin from dark red kidney beans, is stable between 25°C and 70°C, and between pH 4 and pH 11, and in the presence of a variety of divalent metal chlorides at 250 mM concentration. Although DRA, exhibits mitogenic activity toward murine splenocytes, it has no effect on mycelial growth of fungi Botrytis cinerea, Fusarium oxysporum and Mycosphaerella arachidicola.;A novel 13-kDa hemagglutinin is isolated from the golden needle mushroom Flammulina velutipes and is designated as FVA. FVA exhibits mitogenic activity toward murine splenocytes, it has no effect on the activity of mycelial growth in the fungi Botrytis cinerea, Fusarium oxysporum and Mycosphaerella arachidicola.;All the four hemagglutinin cannot be inhibited by a variety of sugars. The activities of the four hemagglutinin are all enhanced for 4 folds after treatment with trypsin (trypsin: PVA = 1:1, w:w) at 37°C. And all of them display no inhibitory effect on the activity of HIV reverse transcriptase (HIV-RT). (Abstract shortened by UMI.)