Chemiluminescent Amersham™ ECL™ Prime is sensitive, stable, and precisely quantitative across a wide dynamic range of protein levels, and is highly efficient in its consumption of expensive antibody reagents. The improved performance of ECL Prime compared with other chemiluminescent reagents is due to the presence of an enhancer in the reagent, increasing enzyme turnover, and thereby significantly increasing both signal intensity and duration. The light signal is further intensified by the addition of a catalyst.