What is the role of pyrophosphate in pyrosequencing?

In pyrosequencing, pyrophosphate plays a crucial role as a signaling molecule that indicates the addition of nucleotides during the sequencing process. When a nucleotide is incorporated into the growing DNA strand by DNA polymerase, pyrophosphate is released. This release triggers a cascade of enzymatic reactions that produce light, which is then detected to provide real-time information about which nucleotide has been incorporated.

This mechanism is fundamental to the pyrosequencing technique, as the emitted light correlates directly with the nucleotide incorporation event, allowing for the sequencing of DNA in a highly efficient manner. By signaling the addition of the correct nucleotide, pyrophosphate enables the identification of the DNA sequence without the need for extensive purification steps or complex amplification techniques used in other methods.