高等学校化学学报Issue(2)：330-335,6.DOI:10.7503/cjcu20140767
多功能淀粉酶固定化中的底物保护效应
Effect of Substrate Material on the Immobilization of Multifunctional Amylase
摘要
Abstract
The catalytic site of the multifunctional amylase OPMA-N occupied a relatively large region in OPMA-N molecule. The optimal conditions to immobilize OPMA-N with hydrogel microspheres of chitosan as a carrier were established by orthogonal experiment as follows:20 mg/mL glutaraldehyde served as cross-linking agent, at 25 ℃, pH=6.5 for 1.5 h, but as long as after the introduction of the substrate-mediated protective effect and conformational memory in order to obtain a stabilized immobilized OPMA-N( IOPMA-N) . This high-lighted the importance of the protective effect of the substrate in the immobilization process of the multifunc-tional enzymes such as OPMA-N in which the catalytic site-covering region generally occupies a larger region in OPMA-N molecule. Compared with the free OPMA-N, IOPMA-N showed more than 3 times apparent activi-ty and more than 4 times catalytic efficiency(kcat/Km) at 50 ℃, pH=6.0—7.0, and had a significantly bet-ter tolerance to the pH from neutral to weakly acidic under moderate temperatures ( 30—50 ℃) . IOPMA-N also exhibited a better operational stability and storage stability by its more than 75% of the apparent activity after 15 times repeated use and 31 d half-life when stored at 4 ℃, while OPMA-N would lose its activity com-pletely after stored 5 d at 4 ℃. Comparative analysis of the catalytic product showed that IOPMA-N exhibited higher hydrolytic activity but slightly lower transglycosyl activity than OPMA-N, which is consistent with the fact that there is a functional( active) balance between hydrolytic and transglycosyl activities in OPMA-N mole-cule, and meanwhile, it also indicated that its substrate had a significant protective effect on its hydrolytic ac-tivity but hardly on its transglycosyl activity in its immobilization.关键词
多功能淀粉酶/壳聚糖/固定化/底物/凝胶微球Key words
Multifunctional amylase/Chitosan/Immobilization/Substrate/Hydrogel microsphere分类
化学化工引用本文复制引用
夏莹,曹昊,张应玖..多功能淀粉酶固定化中的底物保护效应[J].高等学校化学学报,2015,(2):330-335,6.基金项目
国家自然科学基金(批准号:31170759)和吉林省发展和改革委员会项目(批准号:2011003-5)资助 （批准号:31170759）
