雷丸的中性金属蛋白酶的分离纯化、酶学性质及体外驱虫活性

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&;#8226;ml－1 and 21.32 μg&;#8226;min－1&;#8226;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.

Purification, characterization and in vitro anthelmintic activity of a neutral metalloprotease from Laccocephalum mylittae

A neutral metalloprotease was purified from the cultured mycelia ofLaccocephalum mylittae, an effec-tive 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 es-timated by sodium dodecyi sulfate polyacrylamide gel electrophoresis (SDS-PAGE).The optimum reaction pH and temperature are 7.5 and 50℃, respectively.The protease activity is largely enhanced by Ca~(2+), but highly inhibited by tetrasodium ethylenediaminetetraacetate (EDTA), a metal-chelator, suggesting that the enzyme is a metalloprotease.The Michaelis-Menten constan K_m and V_(max) value for casein substrate are 6.09 mg·ml~(-1) and 21.32 μg·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 pro-teins caused by this protease may relate to the anthelmintic activity of L.mylittae.