Catalyzed colorimetric and fluorometric substrates for peroxidase enzyme determinations

Abstract

Improved catalyzed substrates for use in developing characteristic colors or fluorescence in the presence of peroxidase enzymes (e.g., horseradish peroxidase) are disclosed which include as a rate accelerator a substituted phenol such as a p-halogenated phenol. The complete system typically includes a peroxide type oxidizing agent (e.g., hydrogen peroxide), a chromogenic or flurogenic compound (e.g., ABTS), a buffer and the accelerator compound. Advantageously, the accelerator should provide at least about 50 percent rate enhancement for the substrate, as compared with an otherwise identical, accelerator-free substrate reacted under the same conditions; however, the most preferred accelerator, p-iodophenol, gives enhancements on the order to 1,000 percent. The invention is particularly useful in so-called ELISA determinations which involve an enzyme-linked moiety, and permit detection at very low concentration levels unobtainable with conventional colorimetric substrates.

Dependencies are inferred from the claim text.