Direct electrochemistry and electrocatalysis of heme proteins entrapped in agarose hydrogel films in room-temperature ionic liquids

Sheng Fu Wang, Ting Chen, Zhi Ling Zhang, Xin Cheng Shen, Zhe Xue Lu, Dai Wen Pang, Kwok Yin Wong

Research output: Journal article publicationJournal articleAcademic researchpeer-review

355 Citations (Scopus)

Abstract

The electrochemistry and electrocatalysis of a number of heme proteins entrapped in agarose hydrogel films in the room-temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]-[PF6]) have been investigated. UV-vis and FTIR spectroscopy show that the heme proteins retain their native structure in agarose film. The uniform distribution of hemoglobin in agarose-dimethylformamide film was demonstrated by atomic force microscopy. Cyclic voltammetry shows that direct electron transfer between the heme proteins and glassy carbon electrode is quasi-reversible in [bmim][PF 6]. The redox potentials for hemoglobin, myoglobin, horseradish peroxidase, cytochrome c, and catalase were found to be more negative than those in aqueous solution. The charge-transfer coefficient and the apparent electron-transfer rate constant for these heme proteins in [bmim][PF 6] were calculated from the peak-to-peak separation as a function of scan rate. The heme proteins catalyze the electroreduction of trichloroacetic acid and tert-butyl hydroperoxide in [bmim] [PF6]. The kinetic parameter Imax (maximum current at saturation concentration of substrate) and the apparent Km (Michaelis-Menten constant) for the electrocatalytic reactions were evaluated.
Original languageEnglish
Pages (from-to)9260-9266
Number of pages7
JournalLangmuir
Volume21
Issue number20
DOIs
Publication statusPublished - 27 Sep 2005

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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