Herein, an innovative dehydrogenase invoked tri-enzyme cascade has been successfully constructed and utilized as a powerful and universal colorimetric strategy for dehydrogenase-based bioassays. Specifically, the glucose-6-phosphatedehydrogenase (G6PD) catalyzes the specific dehydrogenation of glucose-6-phosphate (G-6-P) by consuming the oxidized form of β-nicotinamide adenine dinucleotide phosphate (NADP⁺) to generate NADPH. And the formed NADPH initiates the irreversible hydroxylation of p-hydroxybenzoate by p-hydroxybenzoate hydroxylase (PHBH) to generate 3,4-dihydroxybenzoate (DHB), which results in the subsequent in situ generation of a photoresponsive nanozyme of DHB coordinated SrTiO₃ (SrTiO₃/DHB) nanosheets. The photoresponsive nanozyme has intriguing interfacial charge transfer (ICT) characteristics and thus realizes the efficiently catalytic oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) under light irradiation for signal readout. Exemplified by G6PD and G-6-P as analytes, the dehydrogenase invoked tri-enzyme cascade achieved efficient signal amplification towards the ultrasensitive colorimetric bioassays. This study opens up the ICT transitions of SrTiO₃ for innovative dehydrogenases-involved enzyme cascades. In addition, it is an entirely new method for dehydrogenases-based bioassays, with the distinctive merits of facile operation, rapid response, high sensitivity, and naked-eye readout. Importantly, it is extensible as a general basis for other numerous targets of interest because of the large numbers of dehydrogenases available for catalysing different reactions.

在这里，创新的脱氢酶称为三酶级联反应已成功构建并用作基于脱氢酶的生物测定的有力且通用的比色策略。具体而言，葡萄糖-6-磷酸脱氢酶（G6PD）通过消耗氧化形式的β-烟酰胺腺嘌呤二核苷酸磷酸（NADP ⁺）来催化葡萄糖6-磷酸（G-6-P）的特定脱氢反应，从而生成NADPH。形成的NADPH通过对羟基苯甲酸酯羟化酶（PHBH）引发对羟基苯甲酸酯的不可逆羟基化反应，生成3,4-二羟基苯甲酸酯（DHB），从而导致原位生成DHB配位SrTiO ₃（SrTiO ₃/ DHB）纳米片。该光敏纳米酶具有吸引人的界面电荷转移（ICT）特性，因此可在光照射下实现3,3'，5,5'-四甲基联苯胺（TMB）的高效催化氧化，以进行信号读出。由G6PD和G-6-P用作分析物，脱氢酶激活的三酶级联反应实现了对超灵敏比色生物测定的有效信号放大。这项研究打开了SrTiO ₃的ICT过渡用于创新的脱氢酶相关酶级联反应。此外，它是基于脱氢酶的生物测定的一种全新方法，具有操作简便，响应速度快，灵敏度高和肉眼读取的独特优点。重要的是，由于大量脱氢酶可用于催化不同的反应，因此它可作为其他众多目标靶标的通用基础进行扩展。