Young Researchers and Elite Club, Shahr-e-Qods Branch, Islamic Azad University, Tehran, Iran.
Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran; Center of Excellence in Biothermodynamics, University of Tehran, Tehran, Iran.
Int J Biol Macromol. 2020 Dec 1;164:4403-4414. doi: 10.1016/j.ijbiomac.2020.09.045. Epub 2020 Sep 12.
Horseradish peroxidase (HRP) was immobilized onto a functionalized reduced graphene oxide-SiO through the covalent bonding process. By using scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR), the formed nanocomposites were characterized. The kinetic parameters including the catalytic constant, k, and the catalytic efficiency, k/K, increased 5.5 and 6 times, respectively, after immobilization. The circular dichroism analysis demonstrated that the α-helical content increased from 39% to 46% after immobilization. The immobilization improved the reusability of HRP as 70% of initial activity retained after 10 cycles. Due to the buffering effect, the immobilized HRP was less sensitive to pH changes as compared to the free HRP. At temperature 40 °C and during 90 min, the immobilized HRP retained 90% of the initial activity while 70% of initial activity remained for the free HRP. After 35-day storage, no reduction in the activity was observed for the immobilized HRP. The removal efficiency for phenol concentration (2500 mg/L) obtained 100% and 50% for the immobilized and free HRP, respectively. The results showed that the immobilized HRP promoted the dyes decolorization from 2-fold until 26-fold as compared to the free HRP. The decolorization efficiencies reached 100% for most dyes in the case of immobilized HRP.
辣根过氧化物酶（HRP）通过共价键过程固定在功能化的还原氧化石墨烯-SiO 上。通过扫描电子显微镜（SEM）和傅里叶变换红外（FT-IR）对形成的纳米复合材料进行了表征。动力学参数包括催化常数 k 和催化效率 k/K，固定化后分别增加了 5.5 倍和 6 倍。圆二色分析表明，固定化后α-螺旋含量从 39%增加到 46%。固定化提高了 HRP 的可重复使用性，10 次循环后保留了初始活性的 70%。由于缓冲效应，与游离 HRP 相比，固定化 HRP 对 pH 变化的敏感性较低。在 40°C 温度下和 90 分钟内，固定化 HRP 保留了初始活性的 90%，而游离 HRP 保留了初始活性的 70%。在 35 天储存后，固定化 HRP 的活性没有下降。对于 2500mg/L 的苯酚浓度，固定化和游离 HRP 的去除效率分别为 100%和 50%。结果表明，与游离 HRP 相比，固定化 HRP 可将染料脱色效率提高 2 倍至 26 倍。对于固定化 HRP，大多数染料的脱色效率达到 100%。
