Precision Plus Protein™ Unstained Standards

Do I need to use StrepTactin with Precision Plus Protein™ standards on my blots?

The Strep-tag affinity tab is a short sequence in each protein of the Precision Plus Protein unstained standards. It has an affinity with native streptavidin. However, StrepTactin is a genetically modified form of streptavidin with a high, optimized affinity for the Strep-tag peptide. For optimal and reproducible results, we highly recommend StrepTactin conjugates:

  • StrepTactin, but not streptavidin, can be used with a wide range of blocking and dilution buffers, including BSA, gelatin, casein, and nonfat dry milk
  • StrepTactin binds evenly to all 10 proteins of the standard, while streptavidin detects higher molecular weight proteins more strongly than lower molecular weight proteins. The use of streptavidin makes it more difficult to control the development of the bands on the blot
  • StrepTactin has less cross-reactivity with endogenous biotin than streptavidin

Precision Protein™ StrepTactin-HRP conjugate, catalog #161-0380 or #161-0381
Precision Protein StrepTactin-AP conjugate, catalog #161-0382