{"title":"Bioelectrocatalytic activity of reconstituted peroxidase on hemin-terminated PQQ-modified electrodes","authors":"Kikuo Komori , Tomoki Aikawa","doi":"10.1016/j.snr.2022.100126","DOIUrl":null,"url":null,"abstract":"<div><p>Efficient direct electrical communication between an enzyme redox center and an electrode is of great interest from the viewpoints of application to reagentless biosensors and biofuel cells. To immobilize redox enzymes in a favorable orientation for electron transfer at the electrode surface, we reconstituted apo-horseradish peroxidase (apo-HRP) onto a hemin cofactor linked to pyrroloquinoline quinone (PQQ) spacer at an indium-tin-oxide (ITO) electrode surface. The bioelectrocatalytic activity of reconstituted HRP for H<sub>2</sub>O<sub>2</sub> reduction was evaluated by means of amperometry at +0.150 V (vs. Ag|AgCl), which value is larger than that for the redox potential of PQQ (ca. –0.140 V). The complex-formation reaction rate of reconstituted HRP with H<sub>2</sub>O<sub>2</sub> enhanced in comparison with that for the hemin linked to PQQ electrode without apo-HRP by a factor of 200. PQQ served as the part of spacer for the insertion of hemin into a certain desired position in apo-HRP. Although native HRP cannot electrochemically communicate with the ITO electrode in general, the quasi-direct electron transfer from the ITO electrode to reconstituted HRP oxidized by H<sub>2</sub>O<sub>2</sub> was also achieved most likely by electron hopping and/or resonant transport without the redox mediation thanks to the π-conjugated PQQ molecule in the spacer.</p></div>","PeriodicalId":426,"journal":{"name":"Sensors and Actuators Reports","volume":null,"pages":null},"PeriodicalIF":6.5000,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666053922000534/pdfft?md5=4584b65857e62a1538a34e2bcd8a5afb&pid=1-s2.0-S2666053922000534-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Sensors and Actuators Reports","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2666053922000534","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"BIOTECHNOLOGY & APPLIED MICROBIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Efficient direct electrical communication between an enzyme redox center and an electrode is of great interest from the viewpoints of application to reagentless biosensors and biofuel cells. To immobilize redox enzymes in a favorable orientation for electron transfer at the electrode surface, we reconstituted apo-horseradish peroxidase (apo-HRP) onto a hemin cofactor linked to pyrroloquinoline quinone (PQQ) spacer at an indium-tin-oxide (ITO) electrode surface. The bioelectrocatalytic activity of reconstituted HRP for H2O2 reduction was evaluated by means of amperometry at +0.150 V (vs. Ag|AgCl), which value is larger than that for the redox potential of PQQ (ca. –0.140 V). The complex-formation reaction rate of reconstituted HRP with H2O2 enhanced in comparison with that for the hemin linked to PQQ electrode without apo-HRP by a factor of 200. PQQ served as the part of spacer for the insertion of hemin into a certain desired position in apo-HRP. Although native HRP cannot electrochemically communicate with the ITO electrode in general, the quasi-direct electron transfer from the ITO electrode to reconstituted HRP oxidized by H2O2 was also achieved most likely by electron hopping and/or resonant transport without the redox mediation thanks to the π-conjugated PQQ molecule in the spacer.
从应用于无试剂生物传感器和生物燃料电池的角度来看,酶氧化还原中心和电极之间有效的直接电通信是非常有趣的。为了将氧化还原酶固定在电极表面有利于电子转移的方向上,我们在铟锡氧化物(ITO)电极表面将载根辣根过氧化物酶(apo-HRP)重组到与吡罗喹啉醌(PQQ)连接的血红素辅因子上。在+0.150 V (vs. Ag|AgCl)电位下,重构HRP对H2O2还原的生物电催化活性比PQQ的氧化还原电位(约-0.140 V)大,与H2O2结合的HRP的络合反应速率比不带载子HRP的hemin连接的PQQ电极提高了200倍。PQQ作为间隔剂的一部分,使血红蛋白插入到载脂蛋白hrp的某个期望位置。虽然原生HRP一般不能与ITO电极进行电化学通信,但由于间隔层中的π共轭PQQ分子,从ITO电极到H2O2氧化的重组HRP的准直接电子转移也很可能是通过电子跳变和/或共振输运实现的,而不需要氧化还原介质。
期刊介绍:
Sensors and Actuators Reports is a peer-reviewed open access journal launched out from the Sensors and Actuators journal family. Sensors and Actuators Reports is dedicated to publishing new and original works in the field of all type of sensors and actuators, including bio-, chemical-, physical-, and nano- sensors and actuators, which demonstrates significant progress beyond the current state of the art. The journal regularly publishes original research papers, reviews, and short communications.
For research papers and short communications, the journal aims to publish the new and original work supported by experimental results and as such purely theoretical works are not accepted.