Abstract: The present invention relates to a method, reagent and kit for detecting ligase-catalyzed joining of nucleic acid ends, and any analyte related thereto, such as a ligase, or a substrate or cofactor thereof. More specifically, the invention relates to a method and kit for detecting the presence or amount of a target nucleic acid sequence in a sample. In the inventive method, ligase-catalyzed joining of nucleic acid ends is detected by detecting the AMP released thereby, preferably by using enzymatic means that comprises luciferase and luciferin.

Abstract: A method for determining inorganic pyrophosphate in a sample, which method comprises contacting the sample with an aqueous reagent comprising xanthosine 5′-monophosphate (XMP) or preferrably inosine 5′-monophosphate (IM), xanthosine phosphoribosyltransferase or preferrably hypoxanthine phosphoribosyltransferase, xanthine oxidase, a divalent cation which is preferrably Mg2+, and a buffering agent which is preferably tris(hydroxymethyl)aminomethane (Tris); and determining production of hydrogen peroxide as a measure or inorganic pyrophosphate in the sample. Preferrably, the reagent further comprises uricase.