Stavn A, Granum P E
Carbohydr Res. 1979 Oct;75:243-50. doi: 10.1016/s0008-6215(00)84643-1.
An extracellular cycloamylose (cyclodextrin) glucanotransferase (EC 2.4.1.19) from Bacillus macerans was purified to homogeneity by adsorption on starch, ammonium sulfate fractionation, column chromatography on DEAE-cellulose, and gel filtration on Sephadex G-100. The enzyme had a molecular weight of 67,000 and consisted of one polypeptide chain. The isoelectric point was pH 5.4. Temperature and pH optima were 60 degrees and 5.4--5.8, respectively. The purified enzyme was quite stable at 50 degrees (pH 6.0), but lost approximately 80% of its activity at 60 degrees for 30 min (pH 6.0). Prolonged digestion by trypsin did not affect the catalytic properties of the enzyme. The Km for starch was 5.7 mg/ml.
从浸麻芽孢杆菌中提取的一种胞外环糊精葡聚糖转移酶（EC 2.4.1.19），通过淀粉吸附、硫酸铵分级分离、DEAE - 纤维素柱层析以及Sephadex G - 100凝胶过滤，被纯化至同质。该酶分子量为67,000，由一条多肽链组成。其等电点为pH 5.4。最适温度和pH分别为60℃和5.4 - 5.8。纯化后的酶在50℃（pH 6.0）时相当稳定，但在60℃下30分钟（pH 6.0）会丧失约80%的活性。胰蛋白酶的长时间消化不影响该酶的催化特性。淀粉的米氏常数（Km）为5.7毫克/毫升。
