Borate-fructose complex: A novel mediator for laccase and its new function for fructose determination

Proposed mechanism of borate-fructose complex as a mediator for ABTS oxidation. The borate-fructose complex is first oxidized by laccase with the concomitant four-electron reduction of oxygen to water, after which it oxidizes ABTS as an electron carrier between laccase and ABTS. Consequently, the change of OD420nm caused by oxidized ABTS is highly related to the concentration of fructose, providing a new strategy for the quantitative analysis of fructose.132