Novel electron transfer mediators based on dichloroindophenol derivatives for lactate oxidase

Novel indophenol derivatives were synthesized and characterized electrochem ically with respect to their abilities to act as electron-transfer mediator s for lactate oxidase. These compounds showed suitable redox potentials and high second-order rate constants, k(med), in solution for electron-transfe r from the reduced enzyme. A lactate sensor using these derivatives demonst rated high sensitivity and good substrate selectivity. This sensor could al so achieve excellent durability which retained more than 70% residual activ ity and good linearity in the range from 0 to 16 mM lactate concentration e ven after 10 days. (C) 2001 Elsevier Science B.V. All rights reserved.