they build up with each addition of a base in the pcr extension and eventually reach such a high concentration that they become enzyme inhibitors and are one factor contributing to poorer pcr efficiency at high cycle numbers

The discussion and very interesting paper onppi initiated by Alejandro Martin at

https://www.researchgate.net/post/Accumulation_of_pyrophosphate_during_PCR

will interest you

Hi Ilyas, the fate would be on PCR reaction rather on pyrophosphates themselves.

But since the PCR product amplification is only exponential in early cycles hence only this data is valuable for us. The lag / plateau phase which is just achieved due to the accumulation of pyrophosphates (diphosphates) and by other reaction artefacts is an indication of the termination of log phase. The ultimate pH drop here is due to the acidic accumulation of these pyrophosphates will at a certain stage shutdown the taq enzyme as well. That is why we only focus on early logarithmic curves (in case of qPCR) by setting the proper thresholds or early cycles when dealing with conventional PCR.

Regards.