Voltammetric Studies of Guanine and Its Derivatives by Ru(bpy)2+/3+ Mediator on Indium Tin Oxide Electrode

摘要

Oxidizing metal complex mediates the electrochemical oxidation of guanine nucleotides. This catalysis results in an enhancement in cyclic voltammograms that yield the rate constant for the oxidation of guanine by the metal complex via digital simulation. The rate constant of oxidation of guanine by Ru(bpy)3(3+) is 6.4 x 10(5)M(-1)s(-l). The rate constant and the enhanced current depend on the number of phosphate groups on the sugar of nucleotidc. Also the modified guanine bases show different oxidation rate constants following the trend guanine-5`- monophosphatc (GMP) > 8-bromo-guanine-5`-monophosphate (8-Br-GMP) > xanthosine -5`-monophosphate (XMP) > inosinc-5`-monophosphate (IMP). The guanine bases derivatized differently are all distinguishable from one another, providing a basis for studying electrochemistry of DNA and RNA and developing electrochemical biosensors.