Practice question

In pyrosequencing, light emission provides quantitative readout of nucleotide incorporation. Once ATP is generated from released pyrophosphate by ATP sulfurylase, firefly luciferase catalyzes the ATP-dependent oxidation of D-luciferin to oxyluciferin, producing a flash of yellow-green light. Emission is captured by a sensitive CCD camera, and peak height correlates with number of identical bases added consecutively. DNA polymerase extends strand, ATP sulfurylase synthesizes ATP, apyrase degrades unincorporated substrates. The distinct role of luciferase is generating photons that enable real-time identification of incorporated nucleotides.