School of Food Science, Henan Institute of Science and Technology, Xinxiang 453003, China.
Molecules. 2018 Oct 24;23(11):2754. doi: 10.3390/molecules23112754.
The sweet potato β-amylase (SPA) was modified by 6 types of methoxy polyethylene glycol to enhance its specific activity and thermal stability. The aims of the study were to select the optimum modifier, optimize the modification parameters, and further investigate the characterization of the modified SPA. The results showed that methoxy polyethylene glycol maleimide (molecular weight 5000, Mal-mPEG5000) was the optimum modifier of SPA; Under the optimal modification conditions, the specific activity of Mal-mPEG5000-SPA was 24.06% higher than that of the untreated SPA. Mal-mPEG5000-SPA was monomeric with a molecular weight of about 67 kDa by SDS-PAGE. The characteristics of Mal-mPEG5000-SPA were significantly improved. The K value, V and in Mal-mPEG5000-SPA for sweet potato starch showed that Mal-mPEG5000-SPA had greater affinity for sweet potato starch and higher speed of hydrolysis than SPA. There was no significant difference of the metal ions' effect on Mal-mPEG5000-SPA and SPA.
采用 6 种甲氧基聚乙二醇对甘薯β-淀粉酶(SPA)进行修饰,以提高其比活力和热稳定性。本研究旨在选择最佳修饰剂、优化修饰参数,并进一步研究修饰后 SPA 的特性。结果表明,甲氧基聚乙二醇马来酰亚胺(分子量 5000,Mal-mPEG5000)是 SPA 的最佳修饰剂;在最优修饰条件下,Mal-mPEG5000-SPA 的比活力比未处理的 SPA 提高了 24.06%。Mal-mPEG5000-SPA 通过 SDS-PAGE 呈单体,分子量约为 67 kDa。Mal-mPEG5000-SPA 的特性得到了显著改善。Mal-mPEG5000-SPA 对甘薯淀粉的 K 值、V 和 表明,Mal-mPEG5000-SPA 对甘薯淀粉具有更大的亲和力和更高的水解速度。Mal-mPEG5000-SPA 和 SPA 对金属离子的影响没有显著差异。