摘要
A neutral metalloprotease was purified from the cultured mycelia of Laccocephalum mylittae,an effective medicinal fungus widely used in anthelmintic therapy.The protease was purified to homogeneity with 31.85-fold purification and a final yield of 21.76%.The subunit molecular weight of the protease is about 40000 estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE).The optimum reaction pH and temperature are 7.5 and 50oC,respectively.The protease activity is largely enhanced by Ca2 +,but highly inhibited by tetrasodium ethylenediaminetetraacetate(EDTA),a metal-chelator,suggesting that the enzyme is a metalloprotease.The Michaelis-Menten constan Km and Vmax value for casein substrate are 6.09 mg·ml -1and 21.32μg·min -1·ml -1, respectively.In vitro anthelmintic tests of the protease exhibit distinct lethal effects on the third stage larvae(L3)of Ascaris suum.Scanning electron microscopy and SDS-PAGE analysis indicates that the proteolysis of larvae proteins caused by this protease may relate to the anthelmintic activity of L.mylittae.
A neutral metalloprotease was purified from the cultured mycelia of Laccocephalum mylittae,an effective medicinal fungus widely used in anthelmintic therapy.The protease was purified to homogeneity with 31.85-fold purification and a final yield of 21.76%.The subunit molecular weight of the protease is about 40000 estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis（SDS-PAGE）.The optimum reaction pH and temperature are 7.5 and 50oC,respectively.The protease activity is largely enhanced by Ca2 ＋,but highly inhibited by tetrasodium ethylenediaminetetraacetate（EDTA）,a metal-chelator,suggesting that the enzyme is a metalloprotease.The Michaelis-Menten constan Km and Vmax value for casein substrate are 6.09 mg·ml -1and 21.32μg·min -1·ml -1, respectively.In vitro anthelmintic tests of the protease exhibit distinct lethal effects on the third stage larvae（L3）of Ascaris suum.Scanning electron microscopy and SDS-PAGE analysis indicates that the proteolysis of larvae proteins caused by this protease may relate to the anthelmintic activity of L.mylittae.
基金
Supported by the National High Technology Research and Development Program of China（2007AA021506）
the Natural Science Foundation of Zhejiang Province（R207609）
