an exoergic chemical reaction that produces a product molecule in an electronically excited state that relaxes via fluorescence or phosphorescence. The intensity of light produced is proportional to the rate of production of the excited state molecule. Chemiluminescent reactions are relatively rare but often involve strong oxidizers (e.g. O3 or H2O2).
The process by which an enzyme is able to catalyze a chemical reaction that results in the production of light. This is commonly used by attaching an enzyme to an antibody. This conjugate is then allowed to bind to a blotted protein mixture on a membrane that has been blocked. If it remains after the wash, it can be used to detect the specific protein to which the antibody has affinity. A subsequent step is needed to add chemicals that react with the conjugated enzyme to produce light that can be detected on X-ray film. It is also used to detect DNA hybridization by adding an antibody step to the detection process, while this works well in most cases; researchers prefer a direct label if possible.