Sachdeva Veena, Hooda Vinita
Department of Botany, Faculty of Life Sciences, Maharshi Dayanand University, Rohtak 124001, India.
Department of Botany, Faculty of Life Sciences, Maharshi Dayanand University, Rohtak 124001, India.
Talanta. 2014 Jun;124:52-9. doi: 10.1016/j.talanta.2014.02.014. Epub 2014 Feb 15.
Nitrate reductase (NR) from Aspergillus niger was covalently coupled to the epoxy affixed gold nanoparticles (epoxy/AuNPs) with a conjugation yield of 35.40±0.01 μg/cm(2) and 93.90±0.85% retention of specific activity. The bare and NR bound epoxy/AuNPs support was characterized using scanning electron microscopy and Fourier Transform Infrared Spectroscopy. The immobilized enzyme system was optimized with respect to pH, temperature and substrate concentrations and successfully employed for determination of nitrate contents in ground water. The minimum detection limit of the method was 0.05 mM with linearity from 0.1 to 10.0 mM. The % recoveries of added nitrates (0.1 and 0.2 mM) were >95.0% and within-day and between-day coefficients of variations were 1.012% and 3.125% respectively. The method showed good correlation (R(2)=0.998) with the popular Griess reaction method. Epoxy/AuNPs bound NR showed good thermal and storage stabilities and retained 50% activity after 16 reuses.
黑曲霉硝酸还原酶（NR）与环氧固定化金纳米颗粒（epoxy/AuNPs）共价偶联，偶联产率为35.40±0.01 μg/cm²，比活性保留率为93.90±0.85%。使用扫描电子显微镜和傅里叶变换红外光谱对裸露的和NR结合的epoxy/AuNPs载体进行了表征。对固定化酶系统的pH、温度和底物浓度进行了优化，并成功用于测定地下水中的硝酸盐含量。该方法的最低检测限为0.05 mM，线性范围为0.1至10.0 mM。添加硝酸盐（0.1和0.2 mM）的回收率>95.0%，日内和日间变异系数分别为1.012%和3.125%。该方法与常用的格里斯反应法具有良好的相关性（R²=0.998）。环氧/AuNPs结合的NR表现出良好的热稳定性和储存稳定性，在重复使用16次后仍保留50%的活性。
