Laboratory of Industrial Microbiology and Biochemistry, University of Leuven, B-3030 Leuven, Belgium.
Appl Environ Microbiol. 1985 Dec;50(6):1474-82. doi: 10.1128/aem.50.6.1474-1482.1985.
The extracellular amylolytic system of Filobasidium capsuligenum consisted of an alpha-amylase (1,4-alpha-d-glucan glucanhydrolase, EC 3.2.1.1) and two forms of glucoamylase (1,4-alpha-d-glucan glucohydrolase, EC 3.2.1.3). The enzymes were purified by ammonium sulfate fractionation, repeated ion-exchange chromatography (DEAE-Sephadex A-50), and gel filtration (Sephadex G-25, Sephadex G-100 sf). alpha-Amylase had an optimum pH of 5.6 and an optimum temperature of 50 degrees C but was rapidly inactivated at higher temperature. The molecular weight was estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be 64,000. An acarbose concentration of 20 mug/ml was required for 50% inhibition of the alpha-amylase. Both glucoamylases are glycoproteins of identical molecular weight (60,000) and produce only glucose by exohydrolysis. The debranching activity of the glucoamylases was evidenced with substrates containing alpha-1,6 linkages. The pH optima were 5.0 to 5.6 for glucoamylase I and 4.8 to 5.3 for glucoamylase II. Glucoamylase I had a higher optimum temperature (55 degrees C) than glucoamylase II (50 degrees C) and was also more resistant to thermal inactivation. Only low acarbose concentrations (<0.1 mug/ml) were required to reduce the activity of the glucoamylases by 50%.
金孢子瓶霉的细胞外淀粉分解系统由α-淀粉酶（1,4-α-D-葡聚糖葡糖水解酶，EC 3.2.1.1）和两种形式的糖化酶（1,4-α-D-葡聚糖葡萄糖水解酶，EC 3.2.1.3）组成。这些酶通过硫酸铵分级沉淀、反复离子交换层析（DEAE-葡聚糖 A-50）和凝胶过滤（葡聚糖 G-25、葡聚糖 G-100 sf）进行纯化。α-淀粉酶的最适 pH 值为 5.6，最适温度为 50°C，但在较高温度下会迅速失活。分子量通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳估计为 64,000。α-淀粉酶的 50%抑制需要阿卡波糖浓度为 20 微克/毫升。两种糖化酶都是分子量相同的糖蛋白（60,000），通过外切水解仅产生葡萄糖。糖化酶具有支链酶活性，可作用于含α-1,6 键的底物。最适 pH 值为 5.0 至 5.6 的是糖化酶 I，4.8 至 5.3 的是糖化酶 II。与糖化酶 II（50°C）相比，糖化酶 I 的最适温度更高（55°C），并且对热失活的抵抗力也更强。仅需低浓度的阿卡波糖（<0.1 微克/毫升）即可使糖化酶的活性降低 50%。
