GoTaq® Master Mixes

What is the difference between the original GoTaq® and GoTaq® G2?

The second-generation recombinant GoTaq® G2 DNA Polymerases offer improved manufacturing consistency compared to the original, ensuring reliable lot-to-lot performance. We also offer the optimized and more cost-efficient GoTaq® G2 Master Mixes. The original native GoTaq® Master Mixes remain available for laboratories with existing standard operating procedures that specify the original formulation.

Can I use GoTaq® Master Mix for RT-PCR?

GoTaq® Master Mixes are designed for the PCR amplification step only. For two-step RT-PCR, first synthesize cDNA using a separate reverse transcriptase (such as GoScript™ Reverse Transcriptase), then use the cDNA as template in a GoTaq® Master Mix reaction. GoTaq® Green Master Mix has been validated for two-step RT-PCR workflows.

What MgCl₂ concentration is in GoTaq® Master Mix?

GoTaq® Master Mixes contain 3mM MgCl₂ at the 2X concentration supplied (final 1.5mM MgCl₂ in the reaction). This concentration works for most primer-template systems. If you need a different Mg²⁺ concentration, consider the GoTaq® Flexi DNA Polymerase, which includes a magnesium-free buffer and a separate 25mM MgCl₂ solution for further optimization. Use the Tm for Oligos Calculator to calculate melting temperatures in Promega buffers. Once the Tm for each primer is known, 5°C below the lowest Tm is a good starting point for the annealing step in PCR. If you see multiple products, try increasing the Tm by 1°C increments until the nonspecific products disappear.

Do I need to change my cycling conditions when switching to GoTaq® Master Mix from another Taq-based method?

No, GoTaq® Master Mixes are formulated for direct substitution into existing Taq-based PCR protocols. Use your established denaturation, annealing, and extension temperatures and times. The extension rate is approximately 1 minute per 1kb of target at 72–74°C.

Will the dyes in GoTaq® Green Master Mix interfere with downstream applications?

The blue and yellow tracking dyes absorb between 225–300nm, which makes standard A260 DNA quantification unreliable and can interfere with fluorescence-based detection like sequencing. If your workflow requires spectrophotometric quantification or fluorescence readouts, use GoTaq® Colorless Master Mix. The dyes do not affect many restriction enzyme digestions, ligation, or sequencing of purified PCR products. See details in this article: Activity of Promega Restriction Enzymes in GoTaq® Green and PCR Master Mixes.

Can I use GoTaq® Master Mix for high-fidelity cloning applications?

GoTaq® DNA Polymerase is a Taq-based enzyme that lacks 3′→5′ proofreading exonuclease activity, so it generates PCR products with A-overhangs suitable for TA cloning. If you need high-fidelity amplification with a lower error rate (for example, expression cloning or site-directed mutagenesis), use a proofreading polymerase instead. For routine cloning and screening where Taq-level fidelity is acceptable, GoTaq® Master Mixes work well.

Is GoTaq® Master Mix compatible with direct gel loading?

Yes, both GoTaq® Green and Colorless Master Mixes produce reactions with sufficient density for direct loading onto agarose gels. GoTaq® Green Master Mix also includes tracking dyes, so you can monitor electrophoresis progress without adding a separate loading buffer.

I accidentally left my GoTaq® on the bench at room temperature overnight. Will it be okay?

Performance cannot be guaranteed outside of the recommended storage conditions. However, Taq polymerase is a robust enzyme, and in most cases the reagent will retain sufficient activity. Test with a positive control to confirm performance before proceeding with critical experiments.