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Updated: Aug 19, 2026

EPR Monitored Redox Titration of the Cofactors of Saccharomyces cerevisiae Nar1
Published on: November 26, 2014
Mediated spectroelectrochemical titration of proteins for redox potential measurements by a separator-less
Seiya Tsujimura1, Atsushi Kuriyama, Nobutaka Fujieda
1Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo, Kyoto 606-8502, Japan.
Abstract:
One-compartment bulk electrolysis and simultaneous spectroscopic measurements are realized in a conventional spectroscopic cuvette without separator by using a mesh-type working electrode with extremely large surface area and a wire-type counter electrode with very small surface area. Spectrophotometric monitoring revealed complete electrolysis in a first-order kinetics. This technique was applied to mediated titration of cytochrome c and bilirubin oxidase for determining their redox potentials. Kinetics for the solution redox reaction between protein and mediator is described. The subtraction of spectral background due to mediator adsorption is very easy because of high reproducibility. The experiments can be done under completely anaerobic conditions. Low-absorbance protein samples (of low concentrations or small absorption coefficients) and hydrophobic proteins (such as membrane-bound proteins) are acceptable for measurements.
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