Laboratory of Bichemistry and Applied Microbiology, São Paulo State University-Unesp, São José do Rio Preto, Brazil.
J Microbiol. 2010 Aug;48(4):452-9. doi: 10.1007/s12275-010-9319-2. Epub 2010 Aug 20.
An alpha-glucosidase enzyme produced by the fungus Thermoascus aurantiacus CBMAI 756 was purified by ultra filtration, ammonium sulphate precipitation, and chromatography using Q Sepharose, Sephacryl S-200, and Superose 12 columns. The apparent molecular mass of the enzyme was 83 kDa as determined in gel electrophoresis. Maximum activity was observed at pH 4.5 at 70 degrees C. Enzyme showed stability stable in the pH range of 3.0-9.0 and lost 40% of its initial activity at the temperatures of 40, 50, and 60 degrees C. In the presence of ions Na(+), Ba(2+), Co(2+), Ni(2+), Mg(2+), Mn(2+), Al(3+), Zn(2+), Ca(2+) this enzyme maintained 90-105% of its maximum activity and was inhibited by Cr(3+), Ag(+), and Hg(2+). The enzyme showed a transglycosylation property, by the release of oligosaccharides after 3 h of incubation with maltose, and specificity for short maltooligosaccharides and alpha-PNPG. The K(m) measured for the alpha-glucosidase was 0.07 microM, with a V(max) of 318.0 micromol/min/mg.
由真菌Thermoascus aurantiacus CBMAI 756 产生的α-葡萄糖苷酶通过超滤、硫酸铵沉淀和使用 Q Sepharose、Sephacryl S-200 和 Superose 12 柱进行色谱法进行纯化。凝胶电泳测定该酶的表观分子量为 83 kDa。最大活性在 pH 4.5 和 70°C 时观察到。该酶在 pH 3.0-9.0 范围内稳定，在 40、50 和 60°C 的温度下失去初始活性的 40%。在离子 Na(+)、Ba(2+)、Co(2+)、Ni(2+)、Mg(2+)、Mn(2+)、Al(3+)、Zn(2+)、Ca(2+)存在下，该酶保持 90-105%的最大活性，并被 Cr(3+)、Ag(+)和 Hg(2+)抑制。该酶具有转糖基化特性，在与麦芽糖孵育 3 小时后释放寡糖，对短麦芽寡糖和α-PNPG 具有特异性。测得的α-葡萄糖苷酶的 K(m)为 0.07 μM，V(max)为 318.0 μmol/min/mg。
