Promotional price valid on web orders only. Your contract pricing may differ. Interested in signing up for a dedicated account number?
Learn More

Thermo Scientific™ Phusion Hot Start II DNA Polymerase (2 U/µL)

Optimize PCR with one of the most accurate hot start DNA polymerases on the market, featuring extreme specificity and improved performance.

Manufacturer:  Thermo Scientific™ F549XL

 View more versions of this product

Catalog No. F549XL

Add to cart



Phusion Hot Start II High Fidelity DNA Polymerase is the most accurate hot start DNA polymerase on the market. It combines the Phusion DNA Polymerase and a reversibly bound, specific Affibody ligand. Affibody inhibits the DNA polymerase activity at room temperature and thus prevents the amplification of nonspecific products.

The Affibody ligand also inhibits the 3´→5´ exonuclease activity of the polymerase, preventing degradation of primers and template DNA during reaction set up. At polymerization temperatures, the ligand is released, rendering the polymerase fully active. Phusion Hot Start II DNA Polymerase does not require a separate activation step in the PCR protocol as it is immediately reactivated at high temperatures.

New Phusion Green Hot Start II High-Fidelity DNA Polymerase is a combination of Phusion Hot Start II 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 Hot Start II DNA Polymerase and is compatible with downstream applications such as DNA sequencing, ligation and restriction digestion.


  • Reaction set up can be done at room temperature
  • Reduces non-specific amplification
  • Prevents primer degradation during set up
  • Zero-time reactivation due to unique hot start technology
  • Extreme fidelity (52X Taq)
  • Speed of the polymerase allows short extension times
  • Robust reactions, minimal optimization needed
  • Increased product yields with minimal enzyme amounts
  • Direct loading on gel with Green Buffer


• Phusion Hot Start II High-Fidelity DNA Polymerase (2 U/µL)
• 5X Phusion HF Buffer
• 5X Phusion GC Buffer
• 50 mM MgCl2 solution

Store at -5 to -30°C.

Built-In Hot Start
Phusion Hot Start II DNA Polymerase
Dry Ice
Provide Content Correction

We continue to work to improve your shopping experience and your feedback regarding this content is very important to us. Please use the form below to provide feedback related to the content on this product.

Product Title

By clicking Submit, you acknowledge that you may be contacted by Fisher Scientific in regards to the feedback you have provided in this form. We will not share your information for any other purposes. All contact information provided shall also be maintained in accordance with our Privacy Policy.

Cancel Submit

Current Phusion Hot Start customers can switch to Phusion Hot Start II with no changes needed to existing protocols or primers. Original Phusion Hot Start will remain available for purchase, however, all new customers are advised to purchase Phusion Hot Start II to allow more flexibility in primer design.