中温淀粉酶的酶学性质研究.pdfVIP

※生物工程 食品科学 2008, Vol. 29, No. 09 373 α 刘 洋，沈 微，石贵阳，王正祥 * (江南大学 工业生物技术教育部重点实验室，江苏 无锡 214122) 通过盐析、DEAE-FF 和 Superdex-75，对Bacillus amyloliquefaciens M23 产生的 α- 淀粉酶进行了纯化， 得到电泳纯的 α- 淀粉酶，纯化倍数为 29.61 ，活力回收率为20.06% 。用SDS测得该酶的分子量为 58kD 。 该酶的最适反应温度为 55 ℃，最适反应pH 值为 6.0 。纯酶液在pH7.0 ～10.0 缓冲液中室温放置 24h ，可保持 80% 以上活力。55 ℃保温 15min，基本丧失活力，添加 10mmol/L 的Ca2+ 能显著提高酶的热稳定性。Ca2+ 、Mg2+ 和 2+ Co 具有激活该酶活性的作用，EDTA 抑制酶的活性。60 ℃，以可溶性淀粉为底物的Km ，Vmax ，分别为4.33g/L 、 1.19g/L ·min 。薄层层析结果表明该酶水解淀粉生成糊精和寡聚糖。 ：Bacillus amyloliquefaciens ；α- 淀粉酶；纯化；性质 Enzymatic Properties of Mesophilic α-Amylase from Bacillus amyloliquefaciens M23 LIU Yang ，SHEN Wei，SHI Gui-yang，WANG Zheng-xiang* (Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China) Abstract：α-Amylase from B. amyloliquefacens M23 was purified to electrophoretic homogeneity. The molecular weight of the purified α-amylase is 58 kD. Its optimum pH value of is in the range from 5.5 to 6.5,and the optimum temperature is 60 ℃. With in 24 h at room temperature 80% enzyme activity keeps in the pH range from 7.0 to 10.0. The most enzyme activity loses 2+ . EDTA inhibits the enzyme within 15 min at 55 ℃. But, the enzyme would be stable for 1 h with the presence of 10 mmol/L Ca 2+ 2+ 2+ m max activity, while, Ca , Mn and Co ions are activators. K and V of α-amylase to soluble starch is 4.33 g/L and 1.19 g/L · min, respectively. The main hydrolysates to soluble starch are oligosaccharides and dextrin. Key wor