What you add is pyrophosphatase, not pyrophosphate. Perhaps it has to do with the use of phi29 polymerase and greater sensitivity of the latter to pyrophosphorolysis. I mean, have you seen an RCA protocol using a different polymerase that also requires pyrophosphatase?

I meant pyrophosphatase not pyrophosphate @Alejandro Martin.

Thanks for the response sir.

Can it then be inferred that the pyrophosphatase which will degrade the pyrophosphate released during the reaction which will sequester the divalent cation needed for the strand synthesis in RCA is necessary it requires 19hrs for completion of RCA, it is mandatory for pyrophosphatase addition in RCA while in PCR it's only at most 3hrs reaction where addition of this enzyme may not be necessary@Alejandro Martin.

Thanks

No, my guess is that it has got nothing to do with sequestration of divalent cations. The problem is that in vitro, some polymerases can also catalyze depolymerization via phosphorolysis (i.e. PPi+DNA -> dNTP + DNA-1) or simply be inhibited by high concentrations of pyrophosphate. So I was speculating that maybe Phi29 polymerase is one such case whereas Taq Pol is not, hence the difference between RCA and PCR. And of course, if that were the case, then RCA protocols employing other polymerases might not require the addition of pyrophosphatase.

Thanks for your response Alejandro Martin

I tend to agree with Alejandro Martin . I also came across some problems doing RCA with phi29 in absence of pyrophosphatase. With dNTP concentration as high as 2 mM or 5 mM, no RCA product was observed. However, with lower dNTP concentration, like 0.2 mM, RCA product could be observed. This might be consistent with what Alejandro claimed, depolymerization via phosphorolysis and inhibition of the enzyme.