Biosynthesis of phytotoxins in phytopathogenic fungi

Neovasifuranones是由植物病原真菌Neocospora vasinfecta NHL 2298产生的植物毒素。最近在从该真菌获得的无细胞系统中观察到neovasifuranone A醛转化为neovasifuranone A。我们研究了这种转化酶的性质，发现有两种酶参与了这一转化步骤。测定了这两种酶的分子量、最适pH、最适温度、Km值和Vmax值。通过离心、DE-52、Sephacryl S-300、TSKgel G3000 SW和Mono Q柱层析，我们还纯化了其中一种酶。最纯的样品在SDS-PAGE分析中显示一条约40 kDa的主要蛋白带。经非变性聚丙烯酰胺凝胶电泳和酶活性测定，确定该带蛋白为酶蛋白。

Neovasifuranones are phytotoxins produced by the phytopathogenic fungus Neocosmospora vasinfecta NHL2298. Recently conversion of neovasifuranone A aldehyde into neovasifuranone A was observed in the cell-free system obtained from this fungus. We studied on the properties of this of this conversion enzyme(s)and found that there are two enzymes involved in this conversion step. We determined the molecular weight, optimal pH, optimal temperature, Km and Vmax values of these two enzymes. We also purified one of these enzymes by centrifugation, DE-52,Sephacryl S-300, TSKgel G3000SW and Mono Q column chromatographies. The purest sample showed one major protein band around 40kDa on SDS-PAGE analysis. This band protein was determined to be an enzyme protein after native PAGE and enzyme assay.