Luminescent Detection of Specific DNA Sequences

The process whereby part of the energy evolved in a chemical reaction is emitted as light is known as luminescence. When luminol is oxidized by hydrogen peroxide in the presence of horseradish peroxidase (HRP), light is evolved ( 1 ). This is shown in Fig. 1 . Luciferin not only enhances the reaction, but prolongs the emission over several minutes ( 2 ). The light may be measured in a luminometer or visualized as the blackening of photographic film, as will be described.   Fig. 1.  Oxidation of luminol in the presence of hydrogen peroxide and HRP (the catalyst).