High-Fidelity PCR

What Is High-Fidelity PCR?

High-fidelity DNA polymerases possess 3' to 5' exonuclease (proofreading) activity that corrects misincorporated nucleotides during DNA synthesis. This correction mechanism reduces the per-cycle error rate by approximately 100-fold compared to standard Taq, which lacks proofreading activity entirely. High-fidelity amplification is critical when sequence accuracy matters. Select a system designed for precise DNA replication.

What you will find:

• High-Fidelity Master Mix: All-in-one 2X formulations like ExtremeTaq™ and MegaFi Pro that streamline your workflow, featuring "Red Mix" variants for direct-to-gel loading.

• High-Fidelity DNA Polymerase: Ultra-pure standalone enzymes such as TruFi™ II and Accuris HF, offering the enhanced processivity required for long-range PCR and site-directed mutagenesis.

How to Choose High-Fidelity PCR Reagents

Polymerase Family
Phusion, Q5, KOD, and Pfu-equivalent polymerases each offer 3' to 5' proofreading exonuclease activity, with differences in processivity, extension speed, and compatibility with GC-rich or difficult templates — selection often depends on the specific template characteristics.

Format
Individual high-fidelity enzymes with optimised HF buffers offer flexibility for custom protocols; 2x high-fidelity master mixes pre-combine components for streamlined high-throughput precision amplification.

Application Requirement
Cloning into expression vectors, site-directed mutagenesis, and any amplicon intended for sequencing benefit substantially from the reduced error rate of high-fidelity enzymes compared to standard Taq.

Template Difficulty
GC-rich templates, long amplicons, or templates with secondary structure may require specific high-fidelity polymerase formulations optimised for these challenges — check product-specific template compatibility notes.

Extension Time Considerations
High-fidelity polymerases often have different optimal extension times and temperatures compared to standard Taq — following the manufacturer's recommended cycling conditions is important for both yield and fidelity.

Specifications Context

High-fidelity DNA polymerases possess 3' to 5' exonuclease (proofreading) activity that detects and removes misincorporated bases immediately after insertion — this correction mechanism reduces the per-cycle error rate to approximately 10⁻⁶ per nucleotide, roughly 50-100 times more accurate than standard Taq. This level of accuracy is required wherever the resulting amplicon will be cloned into an expression vector, used for site-directed mutagenesis, or sequenced, since errors introduced during amplification would be propagated into the final construct or read. High-fidelity enzymes are typically stored at −20 °C with matched HF buffer systems.

Labs adopting high-fidelity PCR for a cloning workflow for the first time should confirm the chosen polymerase's compatibility with their planned downstream assembly method -- blunt-end cloning, TA cloning, or Gibson Assembly -- since some high-fidelity enzymes produce blunt-ended products by default, while others may require an additional A-tailing or end-repair step depending on the specific cloning strategy in use. Running a small-scale test amplification and verifying the product by gel electrophoresis before committing the template to a larger reaction is a useful checkpoint, particularly for difficult or previously unamplified targets. Product availability reflects MBP's catalogue as of mid-2026.

Secure your sequence accuracy—contact the MBP team today for a quote on our professional High-Fidelity PCR solutions.