Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan.
Joint Department of Biomedical Engineering, The University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC 27599, USA.
Int J Mol Sci. 2020 Feb 8;21(3):1137. doi: 10.3390/ijms21031137.
Glucose oxidase (GOx) has been widely utilized for monitoring glycemic levels due to its availability, high activity, and specificity toward glucose. Among the three generations of electrochemical glucose sensor principles, direct electron transfer (DET)-based third-generation sensors are considered the ideal principle since the measurements can be carried out in the absence of a free redox mediator in the solution without the impact of oxygen and at a low enough potential for amperometric measurement to avoid the effect of electrochemically active interferences. However, natural GOx is not capable of DET. Therefore, a simple and rapid strategy to create DET-capable GOx is desired. In this study, we designed engineered GOx, which was made readily available for single-step modification with a redox mediator (phenazine ethosulfate, PES) on its surface via a lysine residue rationally introduced into the enzyme. Thus, PES-modified engineered GOx showed a quasi-DET response upon the addition of glucose. This strategy and the obtained results will contribute to the further development of quasi-DET GOx-based glucose monitoring dedicated to precise and accurate glycemic control for diabetic patient care.
葡萄糖氧化酶（GOx）由于其易得性、高活性和对葡萄糖的特异性，已被广泛用于监测血糖水平。在电化学葡萄糖传感器原理的三代中，基于直接电子转移（DET）的第三代传感器被认为是理想的原理，因为可以在溶液中没有游离氧化还原介体的情况下进行测量，而不会受到氧气的影响，并且在足够低的电势下进行安培测量，以避免电化学活性干扰的影响。然而，天然 GOx 不能进行 DET。因此，人们希望有一种简单、快速的策略来制造具有 DET 能力的 GOx。在本研究中，我们设计了工程 GOx，通过在酶表面上合理引入赖氨酸残基，使其能够一步修饰氧化还原介体（吩嗪乙硫酸酯，PES）。因此，加入葡萄糖后，PES 修饰的工程 GOx 表现出准 DET 响应。该策略和获得的结果将有助于进一步开发基于准 DET GOx 的葡萄糖监测，以实现对糖尿病患者护理的精确和准确的血糖控制。
