CHARACTERIZATION OF ACRIDANCARBOXYLIC ACID-DERIVATIVES AS CHEMILUMINESCENT PEROXIDASE SUBSTRATES

A new class of peroxidase substrates has been developed which produces chemiluminescence upon enzymatic oxidation. A wide variety of N-alkyl acridancarboxylic acid derivatives including esters, thioesters, and s ulfonamides are efficiently oxidized by a peroxidase and a peroxide to enzymatically produce the corresponding chemiluminescent acridinium c ompound, In conjunction with a peroxidase enhancer, continuous light e mission with high light intensities and an extended duration are produ ced, Alternately, an appropriately designed acridan substrate produces a stable acridinium ester intermediate which can be accumulated and t he chemiluminescence elicited as a burst of light by raising the pH. T he effects of leaving groups and substitution on the acridan ring on t he mechanism of light production are discussed, Peroxidase-catalyzed o xidation in the presence of a peroxide permits the detection of enzyme with subattomolar sensitivity and a broad linear dynamic range.