【摘要】 施氏假单胞菌（Pseudomonas stutzeri）F4能产生黄曲霉毒素B₁的降解酶（aflatoxin B₁-degrading enzyme,ADE）,本实验通过3步法提取纯化ADE,即包括硫酸铵分级沉淀、DEAE-Sepharose阴离子交换柱层析和Sephadex G-100凝胶过滤层析。结果表明,通过以上纯化方法,ADE的回收率为56%,纯化的ADE比活力为6.4x10⁴U/mg,纯化了123倍。利用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳测得ADE分子质量约为24kD;ADE与AFB₁反应的最适温度和pH值分别为30℃和6.0;CU²⁺对ADE酶活性有抑制作用;利用双倒数作图法测得ADE表观K_m值为5.61×10^-5mol/L。更多还原

【Abstract】 Aflatoxin B₁（AFB1）-degrading enzyme（ADE） was purified from Pseudomonas stutzeri F4 by a three-step procedure including ammonium sulfate fractional precipitation and chromatography on DEAE-Sepharose and Sephadex G-100.A total of 123-fold purification of ADE with a recovery of 56%and an ultimate specific activity of 6.4× 104 U/mg were achieved.The apparent molecular mass of ADE was estimated to be about 24 kD by SDS-PAGE.The ADE displayed the highest degradation activity for AFB1 at 30 °C and pH 6.0.Cu²⁺ exhibited strong inhibitory activity with an apparent Km of 5.61×10-5mol/L as indicated by the double-reciprocal plot.更多还原