Lei Lei, Liu Jiangtao, Ma Xiao, Yang Hong, Lei Zhongli
Key Laboratory of Applied Surface and Colloid Chemistry, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an, People's Republic of China.
College of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, People's Republic of China.
Biotechnol Appl Biochem. 2019 May;66(3):376-388. doi: 10.1002/bab.1734. Epub 2019 Feb 12.
A dual-stimuli-responsive support material for pectinase immobilization through ionic bonding was prepared. Specifically, polystyrene-b-polymethylacrylic (PS-b-PMAA), light- and pH-sensitive polystyrene-(5-propargylether-2-nitrobenzyl bromoisobutyrate)-b-poly(diethylamino)ethyl methacrylate-b-poly(polyethylene glycol methacrylate) (PS-ONB-PDEAEMA-b-PPEGMA) were synthesized through atom transfer radical polymerization, click chemistry, and hydrolysis. The two parts could self-assemble into the micelles in an aqueous solution. The micelles shrunk at a higher pH, and their size reduced under UV irradiation. The stimuli-responsive properties of micelles were characterized by dynamic light scattering and transmission electron microscopy. It has been found that this support was able to adsorb 10 U/mL of immobilized pectinase (approximately 223 mg/g) at pH 5.0 and 60 °C for 60 Min. Meanwhile, the highest relative activity of immobilized pectinase was up to approximately 95% at pH 5.0 and 60 °C. The immobilized pectinase retained more than 50% of the initial activity after eight cycles. The relative activity of the pectinase immobilized on the supports without UV irradiation was approximately 3% lower than that after UV irradiation at 60 °C, indicating that tailoring of enzyme activity was achieved by changing environmental conditions. Apparently, the original enzymatic support material had a great application prospect on enzyme immobilization.
制备了一种用于通过离子键固定果胶酶的双刺激响应性载体材料。具体而言，通过原子转移自由基聚合、点击化学和水解反应合成了聚苯乙烯-b-聚甲基丙烯酸（PS-b-PMAA）、对光和pH敏感的聚苯乙烯-(5-炔丙基醚-2-硝基苄基溴异丁酸酯)-b-聚（甲基丙烯酸二乙氨基乙酯）-b-聚（聚乙二醇甲基丙烯酸酯）（PS-ONB-PDEAEMA-b-PPEGMA）。这两部分在水溶液中可自组装成胶束。胶束在较高pH值下会收缩，在紫外线照射下其尺寸会减小。通过动态光散射和透射电子显微镜对胶束的刺激响应特性进行了表征。研究发现，该载体在pH 5.0、60℃条件下吸附60分钟，能够吸附10 U/mL的固定化果胶酶（约223 mg/g）。同时，固定化果胶酶在pH 5.0、60℃条件下的最高相对活性高达约95%。固定化果胶酶在经过八次循环后仍保留了超过50%的初始活性。在60℃下，未经过紫外线照射的载体上固定化的果胶酶相对活性比经过紫外线照射后的低约3%，这表明通过改变环境条件实现了酶活性的调控。显然，这种新型酶载体材料在酶固定化方面具有广阔的应用前景。
