Apex BioResearch Products’ 2.0x Taq Master Mix (available from Genesee Scientific) contains everything you need for routine PCR except template and primers. Given the sensitivity of PCR, and its propensity to magnify even minute levels of DNA contamination, anything that serves to decrease the number of pipetting steps, and the number of stock solutions, is a benefit. Since many vendors now carry various types of master mixes, choosing one over another comes down to price and how well the master mix performs in your hands. And, since switching from a tried and true master mix is not something most of us are willing to do without good reason, it helps to have a free sample to try out. I recently took advantage of a free sample offer from Genesee Scientific, the exclusive retailer for Apex BioResearch Products, and compared the Apex™ Master Mix to 2 other products: a standard Taq polymerase, and a high fidelity, fast start enzyme blend.
All 3 amplification reactions contained 30 ng template (pComb3X phagemid containing a human Fab insert), 0.2 µM each forward and reverse primers, 0.2 mM dNTPs, and 0.625 units polymerase. These reagent concentrations were obtained upon diluting the Apex™ Master Mix to 1X. The other 2 reactions were pipetted manually from stock solutions. After an initial denaturing step of 94°C for 2 min, amplification was carried out for 30 cycles of 94°C for 15 sec, 56°C for 30 sec, and 72°C for 2 min. Three microliters out of a total reaction volume of 25 µl were then subjected to agarose gel electrophoresis on a 1% TAE gel containing 1X GelStar® Nucleic Acid Stain (Lonza Inc.). A photo of the gel is shown below.
Lanes 1 and 2 show the amplicon (arrow) obtained with the other 2 vendor’s products and lane 3 shows the amplicon obtained using the Apex™ Master Mix. The Apex™ Master Mix and one of the other products (the high fidelity blend) outperformed the third vendor’s Taq while performing approximately equivalently to each another. All 3 products generated clean amplicons free of nonspecific bands.
In summary, the 2.0X Taq Master Mix from Apex BioResearch Products is very easy to use and works well. The Master Mix is available in package sizes of 100 or 500 reactions (50 µl each). At the advertised price, this works out to $0.66 per reaction for the 100-reaction package and $0.50 per reaction for the 500-reaction size. If you routinely carry out 25 µl reactions, you can halve the cost.
Associate Research Professor
Department of Radiology
Duke University Medical Center