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α-淀粉酶在磁性颗粒上的共价固定化作为高直链淀粉水解的催化剂。

Covalent immobilization of α-amylase on magnetic particles as catalyst for hydrolysis of high-amylose starch.

作者信息

Guo Hui, Tang Yi, Yu Yang, Xue Lu, Qian Jun-Qing

机构信息

College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310014, PR China.

College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310014, PR China.

出版信息

Int J Biol Macromol. 2016 Jun;87:537-44. doi: 10.1016/j.ijbiomac.2016.02.080. Epub 2016 Mar 6.

Abstract

Enzyme immobilized on magnetic particles can be used as efficient recoverable biocatalysts under strong magnetic response. To enable re-use of enzyme, modified Fe3O4 particles were used as carrier to immobilize α-amylase in this paper. Firstly, the surface of Fe3O4 particles were coated with amino groups by direct using TEOS (tetraethoxysilane) followed by treatment with APTES (3-aminopropyltriethoxysilane) and then carboxylated by reacting it with succinic anhydride. In addition, the effect of the immobilization condition on enzyme activity recovery and immobilization efficiency were investigated. The results showed that the optimal immobilization occurred under following conditions: pH 5.5, 40°C, enzyme concentration of 20mgmL(-1), reaction time for 36h. Using immobilized α-amylase as biocatalyst, the optimum pH and temperature for hydrolysis were observed to be 6.5 and 60°C. The kinetics of hydrolysis reaction were studied using Michaelis-Menten equation. The affinity constant (Km) and maximum reaction rate (vmax) of magnetic particles immobilization α-amylase (MPIA) was 0.543mgmL(-1) and 1.321mgmin(-1) compared to those of 0.377mgmL(-1) and 6.859mgmin(-1) of free enzyme. After immobilization, enzymatic activity, storage stability, thermo-stability, and reusability of MPIA were found superior to those of the free one. MPIA maintained 86% enzyme activity after 30 days and maintained 78% enzyme activity after recycling six times.

摘要

固定在磁性颗粒上的酶在强磁响应下可作为高效可回收的生物催化剂。为了实现酶的重复使用,本文使用改性的Fe3O4颗粒作为载体来固定α-淀粉酶。首先,通过直接使用TEOS(四乙氧基硅烷)对Fe3O4颗粒表面进行氨基包覆,随后用APTES(3-氨丙基三乙氧基硅烷)处理,然后使其与琥珀酸酐反应进行羧基化。此外,研究了固定化条件对酶活性回收率和固定化效率的影响。结果表明,在以下条件下发生最佳固定化:pH 5.5、40°C、酶浓度20mgmL(-1)、反应时间36h。以固定化α-淀粉酶作为生物催化剂,观察到水解的最佳pH和温度分别为6.5和60°C。使用米氏方程研究水解反应动力学。磁性颗粒固定化α-淀粉酶(MPIA)的亲和常数(Km)和最大反应速率(vmax)分别为0.543mgmL(-1)和1.321mgmin(-1),而游离酶的分别为0.377mgmL(-1)和6.859mgmin(-1)。固定化后,发现MPIA的酶活性、储存稳定性、热稳定性和可重复使用性均优于游离酶。MPIA在30天后保持86%的酶活性,在循环使用六次后保持78%的酶活性。

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