Department of Chemical and Biomolecular Engineering, University of California, Berkeley 201 Gilman Hall, Berkeley, CA 94720, USA.
Biosens Bioelectron. 2013 Jan 15;39(1):1-13. doi: 10.1016/j.bios.2012.05.043. Epub 2012 Jun 26.
Cytochrome P450s (CYPs) are a large family of heme-containing monooxygenase enzymes involved in the first-pass metabolism of drugs and foreign chemicals in the body. CYP reactions, therefore, are of high interest to the pharmaceutical industry, where lead compounds in drug development are screened for CYP activity. CYP reactions in vivo require the cofactor NADPH as the source of electrons and an additional enzyme, cytochrome P450 reductase (CPR), as the electron transfer partner; consequently, any laboratory or industrial use of CYPs is limited by the need to supply NADPH and CPR. However, immobilizing CYPs on an electrode can eliminate the need for NADPH and CPR provided the enzyme can accept electrons directly from the electrode. The immobilized CYP can then act as a biosensor for the detection of CYP activity with potential substrates, albeit only if the immobilized enzyme is electroactive. The quest to create electroactive CYPs has led to many different immobilization strategies encompassing different electrode materials and surface modifications. This review focuses on different immobilization strategies that have been used to create CYP biosensors, with particular emphasis on mammalian drug-metabolizing CYPs and characterization of CYP electrodes. Traditional immobilization methods such as adsorption to thin films or encapsulation in polymers and gels remain robust strategies for creating CYP biosensors; however, the incorporation of novel materials such as gold nanoparticles or quantum dots and the use of microfabrication are proving advantageous for the creation of highly sensitive and portable CYP biosensors.
细胞色素 P450 酶（CYPs）是一类含有血红素的单加氧酶，参与体内药物和外来化学物质的初次代谢。因此，CYP 反应是制药行业非常关注的问题，药物开发中的先导化合物会被筛选 CYP 活性。体内的 CYP 反应需要辅因子 NADPH 作为电子源，以及另外一种酶，细胞色素 P450 还原酶（CPR）作为电子转移伴侣；因此，任何实验室或工业用途的 CYP 都受到需要提供 NADPH 和 CPR 的限制。然而，如果酶可以直接从电极接受电子，那么将 CYP 固定在电极上就可以消除对 NADPH 和 CPR 的需求。固定化的 CYP 可以作为潜在底物的 CYP 活性检测的生物传感器，尽管只有固定化酶具有电活性时才可以。创建电活性 CYP 的探索导致了许多不同的固定化策略，包括不同的电极材料和表面修饰。这篇综述重点介绍了用于创建 CYP 生物传感器的不同固定化策略，特别是哺乳动物药物代谢 CYP 和 CYP 电极的特性。传统的固定化方法，如薄膜吸附或聚合物和凝胶包封，仍然是创建 CYP 生物传感器的可靠策略；然而，新型材料如金纳米粒子或量子点的结合以及微制造的使用，对于创建高灵敏度和便携式 CYP 生物传感器是有利的。
