Department of Applied Biological Chemistry, Faculty of Agriculture, Tohoku University, Sendai 981, Japan.
Appl Environ Microbiol. 1992 Aug;58(8):2490-4. doi: 10.1128/aem.58.8.2490-2494.1992.
A maltotetraose- and maltotriose-producing amylase which is stable at alkaline pHs and high temperatures was detected in the culture filtrate of a strain of Chloroflexus aurantiacus J-10-F1, a thermophilic, green, photosynthetic bacterium. The enzyme was purified to homogeneity, as demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, by means of ultrafiltration, ammonium sulfate fractionation, and DEAE-cellulose, hydroxyapatite, and high-performance liquid chromatographies. The molecular mass of the purified enzyme was estimated to be about 210,000 Da. The isoelectric point of the enzyme was estimated to be 6.24 by polyacrylamide gel electrofocusing. The amylase was stable up to 55 degrees C and at alkaline pHs of up to 12.0. The optimum pH and temperature of the enzyme activity were 7.5 and 71 degrees C, respectively. Metal ions such as Hg, Zn, Cu, Mn, and Ni strongly inhibited the enzyme activity. The enzyme activity was reactivated specifically by Ca after the enzyme was treated with 1 mM EDTA. This enzyme could digest various kinds of raw-starch granules from corn, cassava, and potato. Both maltotetraose and maltotriose were formed as the main enzymatic products from soluble starch.
一株嗜热、绿色、光合细菌黄化菌（Chloroflexus aurantiacus）J-10-F1 的发酵滤液中存在一种能在碱性 pH 值和高温下稳定的麦芽四糖和麦芽三糖生产型淀粉酶。该酶通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、超滤、硫酸铵分级、DEAE-纤维素、羟磷灰石和高效液相色谱等方法进行了纯化，达到均一性。纯化酶的分子量约为 210,000 Da。通过聚丙烯酰胺凝胶等电聚焦，该酶的等电点估计为 6.24。该淀粉酶在 55°C 以下和碱性 pH 值 12.0 以下稳定。酶活性的最适 pH 和温度分别为 7.5 和 71°C。Hg、Zn、Cu、Mn 和 Ni 等金属离子强烈抑制酶活性。经 1mM EDTA 处理后，该酶可特异性地被 Ca 重新激活。这种酶可以消化来自玉米、木薯和土豆的各种原淀粉颗粒。从可溶性淀粉中形成的主要酶产物是麦芽四糖和麦芽三糖。
