Direct electrochemistry and electrocatalysis of heme proteins entrapped in agarose hydrogel films in room-temperature ionic liquids.
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][PF(6)]) 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][PF(6)]. The kinetic parameter I(max) (maximum current at saturation concentration of substrate) and the apparent K(m) (Michaelis-Menten constant) for the electrocatalytic reactions were evaluated.
Wang
Sheng-Fu
SF
College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, People's Republic of China.
Chen
Ting
T
Zhang
Zhi-Ling
ZL
Shen
Xin-Cheng
XC
Lu
Zhe-Xue
ZX
Pang
Dai-Wen
DW
Wong
Kwok-Yin
KY
D015374:Biosensing Techniques / Q000379:methods*; D002384:Catalysis; D004563:Electrochemistry; D004566:Electrodes; D004579:Electron Transport; D006420:Hemeproteins / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry*; D007700:Kinetics; D010084:Oxidation-Reduction; D012685:Sepharose / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D014238:Trichloroacetic Acid / Q000737:chemistry; D014867:Water / Q000737:chemistry; D020122:tert-Butylhydroperoxide / Q000737:chemistry
D006420:Hemeproteins; D020100:Hydrogels; D014867:Water; D014238:Trichloroacetic Acid; D012685:Sepharose; D020122:tert-Butylhydroperoxide