Pyrosequencing is based on detecting synthesis reactions
In the pyrosequencing process, nucleotides are sequentially added to form the complementary strand of the single-stranded template, to which a sequencing primer has been annealed. The reactions are carried out in the presence of the enzymes DNA polymerase, sulfurylase, and luciferase. One molecule of pyrophosphate (PPi) is released for every nucleotide incorporated into the growing strand by the DNA polymerase and is converted to ATP by sulfurylase. Visible light is produced from luciferin in a luciferase-catalyzed reaction that utilizes the ATP produced by sulfurylase.