根霉α-半乳糖苷酶的三相分离及其酶学性质 |
Three-phase partitioning and characterization of α- galactosidase from Rhizopus sp. A01 |
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中文关键词:棉子糖,蜜二糖,对硝基苯-α-D-吡喃半乳糖苷,三相分离 |
英文关键词:raffinose, melibiose, p-Nitrophenyl-α-d-galactopyranoside, three-phase partitioning |
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中文摘要: |
根霉Rhizopus sp. A01发酵豆渣产α-半乳糖苷酶,粗酶液依次经过三相分离、Sephadex G-100凝胶过滤获得了电泳纯的α-半乳糖苷酶,纯化了6.7倍,总酶活回收率达到46%;凝胶过滤和SDS-PAGE显示该酶为相对分子质量为87.6kDa的单体蛋白。该酶水解对硝基苯-α-D-吡喃半乳糖苷的最适pH值为5.0,最适温度为55℃,表观Km、kcat/Km分别为2.56mmol/L、47,400L/mol·s;能微弱水解蜜二糖和棉子糖,水解蜜二糖的速率是水解棉子糖速率的3.4倍;水解活性受多种 |
英文摘要: |
Using three-phase partitioning flowed by Sephadex G-100 chromatography, a form of α-galactosidase from Rhizopus sp. A01 grown on bean dregs broth was purified to homogeneity with a 6.7-fold increase in specific activity and 46% recovery. The enzyme was showed a monomer with apparent molecular mass of 87.6kDa by SDS-polyacrylamide gel electrophoresis and gel filtration. The α-galactosidase had high activity against p-nitrophenyl-α-d-galactopyranoside (pNPGal) but had slight activity for melibiose and raffinose, and the optimal activity was observed at pH 5.0 and 55℃. The kinetic parameters Km and kcat/Km were 2.56mmol/L and 4.74×104L/mol·s with pNPGal, and the rate of hydrolysise for melibiose was 3.4 times as much as that for raffinose. The enzyme activity was inhibited by all tested metal ions at 5.0mmol/L, and almost completely by Ca2+, Cu2+, Fe3+, Hg+ and Mn2+ among them. The α-galactosidase was highly stable over pH range of 4.5-9.0 at 25℃, and its activity retained approximately 48% of the original activity after incubation for 120min at 55℃. |
王剑锋,王璋,李江,饶军. 根霉α-半乳糖苷酶的三相分离及其酶学性质[J]. 菌物学报, 2012, 31(2): 251-257 |
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