Background Description

Protein purification is the process of isolating the target protein from the total proteins in the experimental sample while still retaining the biological activity and chemical integrity of the target protein. During the construction of vectors, in addition to some necessary expression elements, it is also necessary to consider codon optimization and the choice of tags. Choosing the right tag is not only beneficial for protein purification and promoting protein solubility but also should not affect the structure and function of the protein and downstream applications. This section focuses on introducing His and GST tags.

Table 1. His and GST Tag Introduction

His Tag Protein Affinity Purification

HisSep Ni-NTA Agarose Resin is based on highly cross-linked agarose gel as the matrix, chemically coupled with tetra-coordinated nitrilotriacetic acid (NTA) as the ligand, and after chelating nickel ions (Ni²⁺), it forms a very stable octahedral structure with nickel ions at the center of the octahedron. This structure can protect nickel ions from small molecule attacks. Compared with Ni-IDA resin, it is more stable and can withstand certain concentrations of reducing agents, denaturing agents, or coupling agents under harsh conditions. Compared with Ni-TED resin, it has a larger adsorption capacity for target proteins. It has become one of the indispensable resins for purifying His-tagged proteins in laboratories.

Figure 1. The product principle diagram of His resin.

Table 2. Yeasen His Purification Product Selection Guide

Appendix: HisSep Ni-NTA MagBeads (Cat#20561ES) Product Features

1. Compared with traditional pre-packed columns and resins, there is no need for multiple centrifugation of samples and control of sample flow rate, greatly reducing the purification time.
2. One-step purification can achieve a purity of more than 95% of the target protein.
3. High target protein yield: the yield can reach 70-80%.
4. Can be reused up to 5 times.
5. Easy to adjust the concentration and volume of the target protein.
6. Small protein loss, and no risk of protein denaturation or precipitation.

GST Tag Protein Affinity Purification Media 

GST tag protein affinity chromatography utilizes the covalent affinity between GST fusion protein and fixed glutathione (GSH) through sulfur bonds, and purifies based on the principle of GSH exchange elution. In this purification, a glutathione is combined with the arm of the gel through a sulfur bond, and then the specific action force between glutathione and glutathione S-transferase (i.e., GST-tag) is used to make the GST-tagged fusion protein combine with the arm glutathione on the gel, thereby separating the labeled protein from other proteins. Glutathione usually has oxidized form GSSG and reduced form GSH. When we use GSH elution, GSH will compete with the gel's glutathione to combine with the fusion protein, thereby eluting the target protein.

GSTSep Glutathione Agarose Resin is a GST tag protein purification resin, structurally made by chemically covalently combining reduced glutathione with 6% agarose gel as the matrix through a 12-atom arm. This design has greatly improved the purification efficiency of the resin, enabling it to carry more than 20 mg of GST fusion protein per milliliter of medium. The product has good specificity and cost performance, and can be used to purify various glutathione S-transferase, glutathione-dependent proteins, and glutathione recombinant derivatives in one step.

Table 3. Yeasen GST Purification Product Selection Guide

Appendix: GSTSep Glutathione MagBeads (Cat#20562ES) Product Features

1. Directly purify high-purity target proteins from biological samples through magnetic separation in one step, greatly simplifying the purification process and improving purification efficiency, suitable for convenient GST fusion protein purification in scientific research and industrial fields.
2. Using this magnetic bead for GST Pull-down experiments, since magnetic separation does not require multiple centrifugation and long incubation times, the operation is simpler, faster, and more automated compared to traditional chromatography methods.

Product Information