Learn more about

• What is the importance of (target) protein purification
• Key Benefits
• Protein purification
• Biotin Blocking
• Our Products

In summary

1. The importance of protein purification
2. The challenges of protein purification
3. Biotin blocking
4. Our solutions
   

Protein purification

What is the importance of (target) protein purification?

A protein is one of the most important biological macromolecules. It plays a vital role in cell growth, development, movement, heredity, reproduction, and other life activities.

Protein purification is, in turn, one of the leading applications in biotechnology. Targeted protein purification is a crucial step in enabling protein function analysis without the interference of other molecules. 

A target protein's affinity is a unique property that can efficiently isolate it from other molecules. Other molecular properties, such as the molecular mass, the charge, or the hydrophobicity, can also be used to isolate the target protein; however, these properties can be conflicting between different proteins.

Protein purification

Challenges of protein purification

Efficient purification of large proteins can be challenging. If the agarose has a high density, it is more difficult for large proteins to enter it.

As a result, large target proteins are insufficiently immobilized and remain in the flow-through. The solution to this problem is highly specific Strep-Tactin®XT combined with low-concentrated agarose, Strep-Tactin®XT 4Flow®. 

Strep-Tactin®XT 4Flow® is the resin to start with due to its particular applicability even for low-abundance or challenging proteins. 

In addition, the high-capacity variant of Strep-Tactin®XT 4Flow® can further increase protein yield. 

Challenges with biotin

Biotin blocking

Cell culture supernatants often contain high amounts of free biotin. These become unproblematic when working with Strep-Tactin®XT resins since biotin does neither bind irreversibly to this ligand nor reduces the binding capacity. 

However, this is the case for the application of resins coupled to Strep-Tactin®. Free biotin can bind to the engineered biotin-binding pocket of Strep-Tactin® and prevents the binding of Strep-tag®II or Twin-Strep-tag® proteins. Therefore, biotin must be removed or masked prior to protein purification. The cell internal content of free biotin is relatively low and not a threat to significant inactivation of the Strep-Tactin® resin in protein purification. Besides free biotin, cell lysates also contain small amounts of biotinylated proteins. Due to their low abundance, these proteins do not typically influence the purification results with Strep-Tactin® or Strep-Tactin®XT. 

However, impurities should be prevented when it comes to analytic applications with high sensitivity. The simplest way to eliminate biotin or biotinylated proteins prior to protein purification is irreversibly masking the biotin by adding avidin. 

Avidin, extracted from egg white, is a tetrameric biotin-binding protein (KD for biotin > 10-14) that does not bind to Strep-tag®II or Twin-Strep-tag®. 1 U of avidin is able to block 1 µg of biotin. 

Our Products

Our advice in prevention

At Westburg we offer a wide range of products necessary for protein purification and biotin blocking. Want to find out the unprecedented abilities of the Strep-Tactin®XT 4Flow® purification explore our product range today.

Key benefits

• Higher affinity and protein yield even for large proteins

• Higher capacity for large  proteins

• Broad pH stability (pH 4-10)

• Higher pressure stability compared to Strep-Tactin® Sepharose

• Cost efficiencies

Look at all the products for successful protein purification.

Curious? Take a look at the references