کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
219049 | 463242 | 2013 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Direct electrochemistry and environmental sensing of rice hemoglobin immobilized at graphite electrodes
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موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
مهندسی شیمی (عمومی)
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چکیده انگلیسی
Non-symbiotic hemoglobin from rice (Oryza sativa L.), OsHb-1, with hexacoordinated rather than pentacoordinated heme and high affinity for oxygen, may have a particular role in O2 and environmental sensing. Here, a 21Â kDa monomer OsHb-1 was electrochemically studied at graphite electrodes and further probed in analysis of environmental species such as hydrogen peroxide, cyanide, and superoxide. Redox potential of the OsHb-1 heme iron was found to be â136Â mV vs. SCE, at pH 6.5, while the rate constant ks for the heterogeneous electron transfer (ET) between graphite and OsHb-1 immobilized in the Nafion membrane at the carbon nanotubes-modified electrodes was below 0.2Â sâ1. Despite sluggish ET, OsHb-1 efficiently, with current densities exceeding 2Â mAÂ cmâ2 at â0.3Â V, electrocatalyzed reduction of O2 starting from the potentials of OsHb-1 heme. The bioelectrocatalytic reduction of O2 was partially inhibited by CNâ thus enabling its sensing down to a 100Â pM level. Peroxidase-like activity of OsHb-1 and the reaction of the superoxide anion with the heme iron of OsHb-1, in de-oxygenated solutions, were studied and analysed in terms of OsHb-1 reactivity. The results obtained indicate OsHb-1 is a sensitive tool for environmental biosensing and toxicity screening.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Electroanalytical Chemistry - Volume 704, 1 September 2013, Pages 67-74
Journal: Journal of Electroanalytical Chemistry - Volume 704, 1 September 2013, Pages 67-74
نویسندگان
Beatriz Royo, Maciej Sosna, Aaron C. Asensio, Jose F. Moran, Elena E. Ferapontova,