枯草芽孢杆菌内切木聚糖酶的纯化与性质研究

建立了一种快速、简便分离纯化木聚糖酶的方法。采用活性聚丙烯酰胺凝胶电泳和均质提取法相结合 ,从枯草芽孢杆菌 (Bacillussubtilis)固态培养基发酵产物中分离得到了 2种内切木聚糖酶 ,分别定义为xylⅠ和xylⅡ ,它们水解桦木木聚糖的主要产物有木二糖、木三糖和聚合度更高的木聚寡糖 ,没有木糖。SDS PAGE显示内切木聚糖酶xylⅡ为单肽链结构 ,分子质量为 98 8ku。内切木聚糖酶xylⅡ的酶反应最适温度为 5 0℃ ,酶反应的最适 pH为 7 0。Mn2 + 对xylⅡ酶反应具有促进作用 ,将酶活提高了 2 7倍 ,而Fe3+ 对该酶反应起完全抑制作用。

Purification and Some Properties of Endoxylanases from Bacillus subtilis

A rapid and convenient method based on native polyacrylamide gel electrophoresis and homogenization extraction was used for the purification of xylanase from crude enzymes. Two xylanases were purified by this method from the crude enzyme prepared from Bacillus subtilis. Subsequent analysis with thin layer chromatography and high pressure liquid chromatography indicated that these two xylanases were endo-acting enzymes, designated as xyl I and xyl II. They hydrolyzed xylan mainly to xylobiose, xylotriose and higher short-chain xylooligosaccharides. No xylose was formed. The purified xyl II was a monomeric protein with a molecular weight of 98.8 kDa as determined by SDS-PAGE. The optimum pH and temperature for the action of xyl II were 7.0 and 50℃, respectively. Mn 2+ ions enhanced xyl II enzyme activity by 2.7-fold whereas Fe 3+ completely inhibited enzyme activities.