The mechanism and electron transfer for pollutant dihydric phenol and biomolecule L-Cysteine (L-Cys) interaction in aqueous solution were studied by means of electrochemistry and UV-VIS spectrophotometry. Two forms of L-Cys, fixed on Au-electrode and free dissolved in the solution, were examined. The results showed that L-Cys of an ordered monolayer fixed on an Au electrode facilitated electron transfer and electrocatalytic redox of three isomers of dihydric phenol. However, free L-Cys does not show such facility. Furthermore, neither cleavage of the original chemical bond nor formation of a new chemical bond was observed in the molecules investigated, suggesting that L-Cys molecules may associate tightly with dihydric phenol molecules to form L-Cys · C6H6O2or (L-Cys) 2 · C6H6O2 complex molecule via hydrogen-bonding. Different coordination numbers influence the electrochemical activity and behavior of associated complexes; thus, the function of biomolecules could be affected.
ACKNOWLEDGMENTS
The research is supported by the National Natural Science Foundation of China (Project No. 50478106) and Nanometer Science Foundation of Shanghai, China (Project No. 0452 nm075).