Soft-landed protein voltammetry: a tool for redox protein characterization.
Microperoxidase-11 (MP-11) was first soft landed onto the gold surface of a screen-printed electrode. Intact protein deposition was verified by time-of-flight secondary ion mass spectrometry. The coupling of soft landing with electrochemical techniques allowed unique information to be obtained about the deposition features. A full characterization of the direct electron-transfer properties was performed by modeling data obtained from cyclic voltammetry experiments; calculated values of kinetic electron-transfer constant, formal redox potential, and reorganization energy allow us to hypothesize the mechanism involved in soft landing immobilization and demonstrate the different conformation of the enzyme deposited from two different charged species. The strong interaction between MP-11 and the gold surface and long-term stability of the functionalized electrode characterizes the peculiar features of this procedure, which enhance its power with respect to the existing immobilization procedure and ensure its suitability for those practical applications that could benefit from an unmediated bridgeless bioeletrochemical electron transfer (e.g., biosensor transducers or electrode elements in biofuel cells).
Mazzei
Franco
F
Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, Piazzale Aldo Moro 5, 00185 Roma, Italy. Franco.Mazzei@uniroma1.it
Favero
Gabriele
G
Frasconi
Marco
M
Tata
Alessandra
A
Tuccitto
Nunzio
N
Licciardello
Antonino
A
Pepi
Federico
F
D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D004800:Enzymes, Immobilized; D006046:Gold; D010084:Oxidation-Reduction; D010544:Peroxidases; D011506:Proteins
D004800:Enzymes, Immobilized; D011506:Proteins; D006046:Gold; D010544:Peroxidases; C021799:microperoxidase