Akella Sridevi, Mitra Chanchal K
School of Life Sciences, University of Hyderabad, Hyderabad 500 046, India.
Indian J Biochem Biophys. 2007 Apr;44(2):82-7.
Glutathione (L-gamma-glutamyl-L-cysteinyl-L-glycine; GSH) forms a surface monolayer on gold nanoparticles by tethering via sulfur bonds (Au:GSH). In the present study, glucose oxidase (GOx; EC 1.1.3.4) was immobilized by covalent chemical coupling reactions on to Au:GSH nanoparticles and the enzyme coupled nanoparticles formed a stable colloid (stable for several weeks) in water. The immobilized enzyme was investigated for electrochemical characteristics to monitor the FAD (prosthetic group of the GOx) redox potentials. Various concentrations of substrate (glucose) were added to check the oxidation characteristics. It was observed that with increase in substrate concentrations, the oxidation rate increased proportionally with the current. The present study demonstrated that GOx was effectively coupled to the gold nanoparticle (Au:GSH). The coupled nanoparticle system could be used in a potential biosensor application. Similarly, other enzymes (e.g., horseradish peroxidase) could be immobilized to the Au:GSH nanoparticles via the peptide arm (GSH) to achieve the desired characteristics needed for a specific application in biosensor.
谷胱甘肽（L-γ-谷氨酰-L-半胱氨酰-L-甘氨酸；GSH）通过硫键（Au:GSH）连接在金纳米颗粒表面形成单层。在本研究中，葡萄糖氧化酶（GOx；EC 1.1.3.4）通过共价化学偶联反应固定在Au:GSH纳米颗粒上，且酶偶联纳米颗粒在水中形成稳定的胶体（稳定数周）。对固定化酶的电化学特性进行研究以监测FAD（GOx的辅基）的氧化还原电位。添加不同浓度的底物（葡萄糖）以检查氧化特性。观察到随着底物浓度增加，氧化速率与电流成比例增加。本研究表明GOx有效地偶联到了金纳米颗粒（Au:GSH）上。偶联纳米颗粒系统可用于潜在的生物传感器应用。同样，其他酶（如辣根过氧化物酶）可通过肽臂（GSH）固定到Au:GSH纳米颗粒上，以实现生物传感器特定应用所需的理想特性。
