FAQ: What is the activity of Thermostable USER® III Enzyme in other buffers?

Thermostable USER III Enzyme is 100% active in Thermopol Buffer and has limited activity in other buffers. Activity in NEBuffers at 65°C is as follows:  

NEBuffer r1.1 r2.1 r3.1 rCutSmart
% Activity 100 50 50 75

Additionally, Thermolabile USER II Enzyme is 100% active in many polymerase and PCR buffers (see chart below).

Buffer Activity (Relative to Thermopol Buffer)
Thermopol II Reaction Buffer (NEB #B9004) 100%
Q5® Reaction Buffer (NEB #B9027) 50%
Colorless GoTaq® Flexi Buffer (Promega®) 75%
PCR Buffer (Qiagen®) 75%
iTaq Buffer 100%
AmpliTaq Gold® 360 Buffer (ThermoFisher®) 100%
Fast Start™ Taq DNA Pol PCR Buffer (Sigma Aldrich) 0%
Ex Taq Buffer (Takara) 0%
Dream Taq Buffer (ThermoFisher®) 75%
Platinum II PCR Buffer (Invitrogen) 75%


  • AmpliTaq Gold® and Thermo Fisher® are registered trademarks and property of Thermo Fisher Scientific.
  • GoTaq® and Promega® are registered trademarks of Promega, Inc.
  • Qiagen® is a registered trademark of Qiagen, Inc.
  • Fast Start™ is a trademark of Sigma Aldrich.