A novel material MnO2 nanosheet has been used as the support matrix for the immobilization of horseradish peroxidase (HRP). HRP entrapped in MnO2 nanosheet film exhibits facile direct electron transfer with the electr...A novel material MnO2 nanosheet has been used as the support matrix for the immobilization of horseradish peroxidase (HRP). HRP entrapped in MnO2 nanosheet film exhibits facile direct electron transfer with the electron transfer rate constant of 6.86 s-1. The HRP/MnO2 nanosheet film gives a re- versible redox couple with the apparent formal peak potential (E0′) of -0.315 V (vs. Ag/AgCl) in pH 6.5 phosphate buffer solution (PBS). The formal potential E0′ of HRP shifts linearly with pH with a slope of -53.75 mV·pH-1, denoting that an electron transfer accompanies single-proton transportation. The immobilized HRP shows an electrocatalytic activity to the reduction of H2O2. The response time of the biosensor for H2O2 is less than 3 s, and the detection limit is 0.21 μmol·L-1 based on signal/noise = 3.展开更多
Fifteen non-aminoazo, dyes were oxidized when catalyzed by horseradish peroxidase (HRP) in the presence of H2O2. Aromaticdiazonium ions, the ultimate carcinogen, were detected in the reaction with all of azo compounds...Fifteen non-aminoazo, dyes were oxidized when catalyzed by horseradish peroxidase (HRP) in the presence of H2O2. Aromaticdiazonium ions, the ultimate carcinogen, were detected in the reaction with all of azo compounds as the substrates for HRP. The rates of oxidative cleavage fairly depended on pH. Relative enzymatic activities were compared among 15 non-aminoazo, dyes, and the structural requirements of the substrates for HRP were discussed in detail.展开更多
基金the National Natural Science Foundation of China (Grant No. 20301002)the National 863 Program of China (Grant No. 2006AA03Z343)
文摘A novel material MnO2 nanosheet has been used as the support matrix for the immobilization of horseradish peroxidase (HRP). HRP entrapped in MnO2 nanosheet film exhibits facile direct electron transfer with the electron transfer rate constant of 6.86 s-1. The HRP/MnO2 nanosheet film gives a re- versible redox couple with the apparent formal peak potential (E0′) of -0.315 V (vs. Ag/AgCl) in pH 6.5 phosphate buffer solution (PBS). The formal potential E0′ of HRP shifts linearly with pH with a slope of -53.75 mV·pH-1, denoting that an electron transfer accompanies single-proton transportation. The immobilized HRP shows an electrocatalytic activity to the reduction of H2O2. The response time of the biosensor for H2O2 is less than 3 s, and the detection limit is 0.21 μmol·L-1 based on signal/noise = 3.
基金Project supported by the National Natural Science Foundation of China.
文摘Fifteen non-aminoazo, dyes were oxidized when catalyzed by horseradish peroxidase (HRP) in the presence of H2O2. Aromaticdiazonium ions, the ultimate carcinogen, were detected in the reaction with all of azo compounds as the substrates for HRP. The rates of oxidative cleavage fairly depended on pH. Relative enzymatic activities were compared among 15 non-aminoazo, dyes, and the structural requirements of the substrates for HRP were discussed in detail.
