کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10796049 | 1052655 | 2008 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Direct electron transfer from graphite and functionalized gold electrodes to T1 and T2/T3 copper centers of bilirubin oxidase
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
کلمات کلیدی
EDCSPGEΔEpIET1-DecanethiolN-hydroxysuccinimideNHSMPADETBODBioelectrocatalysis4-aminothiophenol - 4-آمینوتیوفنول6-Mercapto-1-hexanol - 6-مرکاپتو-1-هگزانولN-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride - N- (3-dimethylaminopropyl) -N'-ethylcarbodiimide hydrochloride3-Mercaptopropionic acid - اسید 3-مروپپروپرونیکelectron transfer - انتقال الکترونdirect electron transfer - انتقال الکترون مستقیمBilirubin oxidase - بیلیروبین اکسیدازElectron transfer kinetics - جنبش انتقال الکترونSurface concentration - غلظت سطحCyclic voltammogram - ولتاموگرافی سیکلیmidpoint redox potential - پودر reddo midpoint
موضوعات مرتبط
علوم زیستی و بیوفناوری
علوم کشاورزی و بیولوژیک
دانش گیاه شناسی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Direct electron transfer (DET) from bare spectrographic graphite (SPGE) or 3-mercaptopropionic acid-modified gold (MPA-gold) electrodes to Trachyderma tsunodae bilirubin oxidase (BOD) was studied under anaerobic and aerobic conditions by cyclic voltammetry and chronoamperometry. On cyclic voltammograms nonturnover Faradaic signals with midpoint potentials of about 700Â mV and 400Â mV were clearly observed corresponding to redox transformations of the T1 site and the T2/T3 cluster of the enzyme, respectively. The immobilized BOD was differently oriented on the two electrodes and its catalysis of O2-electroreduction was also massively different. On SPGE, where most of the enzyme was oriented with the T1 copper site proximal to the carbon with a quite slow ET process, well-pronounced DET-bioelectroreduction of O2 was observed, starting already at >Â 700Â mV vs. NHE. In contrast, on MPA-gold most of the enzyme was oriented with its T2/T3 copper cluster proximal to the metal. Indeed, there was little DET-based catalysis of O2-electroreduction, even though the ET between the MPA-gold and the T2/T3 copper cluster of BOD was similar to that observed for the T1 site at SPGE. When BOD actively catalyzes the O2-electroreduction, the redox potential of its T1 site is 690Â mV vs. NHE and that of one of its T2/T3 copper centers is 390Â mV vs. NHE. The redox potential of the T2/T3 copper cluster of a resting form of BOD is suggested to be about 360Â mV vs. NHE. These values, combined with the observed biocatalytic behavior, strongly suggest an uphill intra-molecular electron transfer from the T1 site to the T2/T3 cluster during the catalytic turnover of the enzyme.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - Bioenergetics - Volume 1777, Issue 10, October 2008, Pages 1364-1369
Journal: Biochimica et Biophysica Acta (BBA) - Bioenergetics - Volume 1777, Issue 10, October 2008, Pages 1364-1369
نویسندگان
Pablo RamÃrez, Nicolas Mano, Rafael Andreu, Tautgirdas Ruzgas, Adam Heller, Lo Gorton, Sergey Shleev,