Phusion High-Fidelity DNA Polymerase

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The most accurate thermostable DNA Polymerase available offering superior performance for cloning and other applications requiring high fidelity.

Phusion High-Fidelity DNA PolymeraseThermo Scientific Phusion DNA Polymerases set a gold standard for PCR performance. They offer a combination of characteristics that no other enzyme can match. Featuring an error rate 50-fold lower than that of Taq, and 6-fold lower than that of Pfu, Phusion DNA Polymerase is the most accurate thermostable polymerase available. This feature makes Phusion DNA Polymerases superior choice for cloning and other applications requiring high fidelity. The unique structure of the enzyme enables short protocol times, abundant yields and robust performance, even in the presence of PCR inhibitors. For the researcher, that translates to ease-of-use and convenience. In addition, Phusion DNA Polymerases also produce higher yields with lower enzyme amounts than other DNA polymerases.

New Phusion Green format is a combination of Phusion DNA Polymerase and 5X Phusion Green Buffers. The buffers include a density reagent and two tracking dyes for direct loading of PCR products on a gel. The colored buffer does not interfere with excelent performance of Phusion DNA Polymerases and is compatible with downstream applications such as DNA sequencing, ligation and restriction digestion.

Phusion High-Fidelity PCR Master Mixes are convenient 2X mixes designed to minimize the number of pipetting steps. Only template and primers need to be added by the user. Phusion High-Fidelity PCR Kit contains all the necessary reagents for PCR including control template and primers.

Phusion PolymerasesDID YOU KNOW?

The optimal annealing temperature for Phusion DNA Polymerases may differ significantly from that of Taq-based polymerases.

For optimal results start by accurately calculating your Tm with our Tm calculator.


  • Extreme fidelity (error rate 4.4 x 10-7 in Phusion HF Buffer)
  • Polymerase speed allows short extension times (15 to 30 s/kb)
  • Robust performance, minimal optimization needed
  • Increased product yields with minimal enzyme amounts
  • Direct loading on gel with Green Buffer


  • High performance PCR
  • High-fidelity PCR
  • Cloning
  • Sequencing (template generation)
  • High throughput
  • Difficult (GC-rich) templates
  • Template generation for sequencing
  • Long-range PCR
  • Cloning
  • Mutagenesis†
  • Microarray


Phusion High-Fidelity DNA Polymerase (F-530):

  • Phusion DNA Polymerase 2 U/μL
  • 5X Phusion HF Buffer
  • 5X Phusion GC Buffer
  • DMSO
  • 50 mM MgCl2 solution

Both Phusion HF Buffer and Phusion GC Buffer provide 1.5 mM MgCl2 in the final 1X concentration.

Phusion Green High-Fidelity DNA Polymerase (F-534):

  • Phusion DNA Polymerase 2 U/µL
  • 5X Phusion Green HF Buffer
  • 5X Phusion Green GC Buffer
  • DMSO
  • 50 mM MgCl2

Both Phusion Green HF and Phusion Green GC Buffer provide 1.5 mM MgCl2 in the final 1X concentration.

Phusion High-Fidelity PCR Master Mix with HF Buffer (F-531):

  • Phusion DNA Polymerase, 400 μM of each dNTP and 2X Phusion HF Buffer
  • DMSO

Phusion High-Fidelity PCR Master Mix with GC Buffer (F-532):

  • Phusion DNA Polymerase, 400 μM of each dNTP and 2X Phusion GC Buffer
  • DMSO

Master mixes provide 1.5 mM MgCl2 and 200 μM dNTP in final reaction concentration.

Phusion High-Fidelity PCR Kit (F-553):

  • Phusion DNA Polymerase 2 U/μl
  • 5X Phusion GC Buffer
  • 5X Phusion HF Buffer
  • dNTP mix (10 mM each)
  • MgCl2 solution (50 mM)
  • Control template (λ DNA)
  • 1.3 kb primers (4 μM each)
  • 10 kb primers (4 μM each)
  • DNA size standard
  • DMSO


Phusion Site-Directed Mutagenesis Kit also available.

Shelf Life0 Months,36 Months
Shipping ConditionDry Ice
Storage buffer20 mM Tris-HCl (pH 7.4 at 25 °C), 0.1 mM EDTA, 1 mM DTT, 100 mM KCl, stabilizers, 200 µg/mL BSA and 50 % glycerol.
Storage Condition-20 C
Fidelity comparison

Extreme fidelity for demanding PCR

Fidelity comparison

Relative fidelity values of different DNA polymerases. Phusion DNA Polymerases have extremely low error rates. The error rate, determined by a modified lacI-based method, is approximately 50-fold lower than that of Taq DNA polymerase and 6-fold lower than that of Pfu DNA polymerase. Fidelity = 1 / error rate.

gel images

Phusion DNA Polymerase combines extreme fidelity with unparalleled speed and robustness

gel images

A random set of 16 clones from a Thermus sp. genomic library was amplified from bacterial colonies. The results highlight the robustness and speed of Phusion DNA Polymerase. It was able to amplify 94% of the amplicons with lower enzyme amounts still producing superior yields. The success rate of Pfu DNA polymerase was only 56% and that of Taq DNA polymerase 62% with significantly lower yields.

gel image

Less enzyme - superior yield

gel image

A 3.8 kb fragment from human beta globin gene was amplified with three different DNA polymerases. Phusion DNA Polymerase was able to amplify the 3.8 kb genomic fragment with a combined annealing and extension step of only 1 minute, thus being significantly faster than the two other polymerases tested. A single unit of Phusion DNA Polymerase produced higher yields than 2.5 or 5 units of the Pfu DNA polymerases.

Agarose gel image showing enhanced yield of PCR products from 20 kb viral DNA and 7.5 kb genomic DNA templates using Phusion and Phusion Green proofreading DNA polymerases

Superior yields of long PCR products

Agarose gel image showing enhanced yield of PCR products from 20 kb viral DNA and 7.5 kb genomic DNA templates using Phusion and Phusion Green proofreading DNA polymerases

20 kb fragment from λ DNA and 7.5 kb fragment from human genomic DNA was amplified with Phusion and proofreading DNA polymerase from other suppliers. Phusion and Phusion Green DNA Polymerases were the only enzymes capable of providing high amounts of desired PCR products. In contrast, other proofreading polymerases delivered zero or significantly lower yields.

Agarose gel image showing high-yield amplicons produced from GC-enriched templates. A similar product from a competitor was unable to amplify from an 85% GC-enriched template while Phusion robustly amplified this template.

Robust amplification of DNA fragments regardless of GC content

Agarose gel image showing high-yield amplicons produced from GC-enriched templates. A similar product from a competitor was unable to amplify from an 85% GC-enriched template while Phusion robustly amplified this template.

Four DNA fragments of different GC content were amplified. Phusion Green DNA Polymerase produced all four amplicons with high yields. In contrast, competing high fidelity DNA polymerase was not able to efficiently produce GC-rich content.



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