摘要
从Bacillus sp．中分离纯化了一种新的中温酸性α-淀粉酶，并对其酶学性质进行了研究，粗酶经硫酸铵沉淀、DEAE—Sepharose Fast Flow阴离子层析、Sephadex G-75凝胶过滤层析等步骤后获得电泳均一的α-淀粉酶，其分子量（Mr）约为56X10^3，该酶最适反应pH为5．0，在pH5．0～11．0范围内稳定，具有较好的耐酸特性，该酶最适反应温度为40～50℃，在40～60℃范围内稳定，在60℃、pH4．5时，该酶能快速有效水解可溶性淀粉；在pH5．0时该酶对多种生淀粉底物也具有良好的水解作用，因此，该酶有助于解决中温条件淀粉加工行业中，液化酶和糖化酶由于适用pH值的差异而无法联用的难题，是一种具有研究价值和应用前景的中温酸性α-淀粉酶，经LC—MASS—MASS分析得到了酶蛋白中两个肽段的氨基酸序列，通过比对发现，该酶与NCBI中已报道的α-淀粉酶序列具有一定的同源性，同时，在氨基酸水平上也存在着差异。
A novel acid-stable α-amylase from Bacillus sp. was purified reaching 34 folds of electrophoretic homogeneity by sequential ammonium sulfate precipitation, DEAE-Sepharose Fast Flow chromatography and Sephadex G-75 chromatography. The enzyme had a molecular weight of 56 × 10^3 estimated by SDS-PAGE. The purified α-amylase exhibited the maximum activity at pH 5.0 and 40 - 50 ℃. Furthermore, the enzyme performed stable over the pH range of 5.0 - 11.0 and at 60 ℃. The enzyme preparation could efficiently hydrolyze soluble starch at pH 4. 5, and hydrolyze various raw starches very well at pH 5.0. These features are very important for industrial starch liquefaction. From the application point of view, this α-amylase could be a potential candidate for synergistic use along with amyloglucosidase in starch processing industry. The amino acid sequences of two peptides from the purified enzyme were analyzed by LC-MASS-MASS, and the enzyme did not show strict identity to the α-amylases reported for some differences in amino acid residues. Fig 6, Tab 1, Ref 20
出处
《应用与环境生物学报》
CAS
CSCD
北大核心
2008年第2期235-239,共5页
Chinese Journal of Applied and Environmental Biology
基金
长江学者和创新团队发展计划资助项目(IRT0532)~~
关键词
中温酸性
Α-淀粉酶
生淀粉
纯化
酶学性质
acid-stable α-amylase
raw starch
purification
enzymatic property
