An analyte sensor for use in connection with a biofluid is described. The analyte sensor may comprise any suitable interface between the biofluid and a derivative of the biofluid and any suitable transducer of information concerning an analyte. At least one catalytic agent is provided in a locale or vicinity of the interface. The catalytic agent, such as a proteinaceous agent or a non-proteinaceous, organic-metal agent, is sufficient to catalyze the degradation of reactive oxygen and/or nitrogen species that may be present in the vicinity of the interface. An analyte-sensing kit and a method of sensing an analyte are also described.