BrightStar AP is a sensitive, chemiluminescent substrate for alkaline phosphatase that allows for the rapid, reproducible detection of alkaline phosphatase-labeled molecules. BrightStar AP is supplied as a 0.25 mM ready-to-use aqueous solution, with no dilution necessary, for use in a variety of membrane-based applications, including Northern, Southern, and colony lift blots. BrightStar AP functions on both neutrally-charged and positively-charged membrane, giving the reagent added application versatility.