Is it important to have a dNTP preparation free from tetraphosphates?
Yes. Chemical dNTP synthesis is normally carried out by unspecific addition of PPi to dNMPs. If PPi is accidentally added to dNDPs this will result in the formation of tetraphosphates, which may cause strand termination (smearing) and other PCR problems. This is especially important in long-distance PCR applications and Reverse Transcription of long fragments. Such problems are not encountered with enzymatically synthesised dNTPs, since phosphorylation is carried out using very specific enzymes that only incorporate one phosphate group at a time. * PCR is a registered Trademark Roche Molecular Systems.
