Diazonium-functionalized horseradish peroxidase immobilized via addressable electrodeposition: direct electron transfer and electrochemical detection.
A simple one-step procedure is introduced for the preparation of diazonium-enzyme adducts. The direct electrically addressable deposition of diazonium-modified enzymes is examined for electrochemical sensor applications. The deposition of diazonium-horseradish peroxidase leads to the direct electron transfer between the enzyme and electrode exhibiting a heterogeneous rate constant, ks, of 10.3 +/- 0.7 s-1 and a DeltaEp of 8 mV (v = 150 mV/s). The large ks and low DeltaEp are attributed to the intimate contact between enzyme and electrode attached by one to three phenyl molecules. Such an electrode shows high nonmediated catalytic activity toward H2O2 reduction. Future generations of arrayed electrochemical sensors and studies of direct electron transfer of enzymes can benefit from protein electrodes prepared by this method.
Polsky
Ronen
R
Sandia National Laboratories, Albuquerque, New Mexico 87185, USA.
Harper
Jason C
JC
Dirk
Shawn M
SM
Arango
Dulce C
DC
Wheeler
David R
DR
Brozik
Susan M
SM
D002627:Chemistry, Physical / Q000379:methods; D003979:Diazonium Compounds / Q000494:pharmacology*; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D004583:Electrons; D004595:Electroplating / Q000379:methods*; D004798:Enzymes / Q000737:chemistry; D004800:Enzymes, Immobilized / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D013997:Time Factors
D003979:Diazonium Compounds; D004798:Enzymes; D004800:Enzymes, Immobilized; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase