The Streptavidin AP LumiBlot™ Kit is designed for convenient, sensitive detection of immobilized biotinylated proteins and other macromolecules by chemiluminescence. Detection is based on the binding of streptavidin-alkaline phosphatase conjugate (Streptavidin AP) to the biotinylated target molecule, followed by development with CDP-Star® substrate. The chemiluminescent signal can be detected by exposure to standard x-ray film and is also compatible with standard instrumentation having chemiluminescent detection capability. Kit reagents and protocol are optimized for high signal and minimal nonspecific background in Western blot applications. Under the conditions recommended in the kit, less than 1 ng of biotinylated protein can be detected in a single band on Western blots.