Caister Academic Press

Taq Concentration

Edited by: Jim Huggett and Justin O'Grady
"I would highly recommend this book" (Doodys); "useful new insights" (Aus. J. Med. Sci.)
In a PCR experiment approximately 1 unit of the Taq enzyme should be used for a 25μl reaction. Suboptimal concentration of the Taq enzyme can cause incomplete primer elongation or premature termination of the PCR product synthesis during the elongation step of a PCR cycle.

Too much Taq will result in an excessive background of unwanted DNA fragments (a smear on a gel) while a huge excess may cause the reaction to fail with no product being detected. A Taq concentration of 1 unit per 25μl reaction ensures a cleaner product and lower background.

from PCR Troubleshooting: The Essential Guide see also PCR Troubleshooting and Optimization: The Essential Guide

Further reading