基于短孔道Zr-Ce-SBA-15固定胃蛋白酶的活性生物催化剂

在不外加无机酸的条件下, 通过水热合成法制备了短孔道六方板状有序介孔材料Zr-Ce-SBA-15 (ZCS). 以ZCS和传统SBA-15为载体对胃蛋白酶进行固定, 并利用N-(2-氨乙基)-3-氨丙基三甲氧基硅烷(AAPTS)对酶固定化材料进行功能化, 以缩小开口孔径从而减少酶泄漏. 采用小角X射线衍射、扫描电镜、透射电镜、氮气吸附和红外光谱对样品进行结构表征. 结果表明, 胃蛋白酶成功固定到介孔孔道中, AAPTS嫁接到材料中且没有破坏介孔结构. 固定化实验表明相比于SBA-15, ZCS对胃蛋白酶具有较快的吸附速度和较强的固定化能力(最大负载量为257.9 mg/g), 短孔道材料能有效地促进分子的扩散传递. 催化活性测定以牛血红蛋白为探针物, 与游离酶相比, 固定酶对牛血红蛋白保持着稳定的活性.

Active Biocatalysts Based on Pepsin Immobilized in Short Channeled Zr-Ce-SBA-15

Short channeled Zr-Ce-SBA-15(ZCS) mesoporous materials with hexagonal platelet morphologies were synthesized through a hydrothermal route without addition of mineral acids.Porcine pepsin was immobilized inside ZCS and conventional SBA-15 through physical adsorption.A grafting step with 1-(2-amino-ethyl)-3-aminopropryl] trimethoxysilane(AAPTS) was performed to reduce the pore openings of the host material in order to minimize the enzyme leaching.The hybrid materials were characterized by X-ray diffraction,scanning electron microscope,transmission microscope,N2 adsorption/desorption and Fourier-transform infrared spectroscope.The results confirmed that pepsin is located inside the channels of the mesoporous materials and the grafting process does not affect the mesoporous structure.The immobilization of pepsin into ZCS and SBA-15 were compared.The results demonstrate that the ZCS materials have higher adsorption rates and adsorption capacities(the maximum adsorption capacity is 257.9 mg/g) compared with SBA-15.The ZCS materials with short channels are superior to conventional SBA-15 facilitating molecular diffusion.The catalytic activity of the hybrid bioinorganic material was tested with hemoglobin.The immobilized pepsin has maintained the necessary degree of freedom to fulfill its catalytic activity.