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GST or His-tagged Protein Purification Service

1 GST Fusion Protein Purification Service:


GST stands for Glutathione S-transferase. It is a 211 amino acid protein (26 kDa) whose DNA sequence is frequently integrated into expression vectors for production of recombinant proteins. GST is typically fused to the N-terminus of a recombinant protein through recombinant DNA technology. GST fusion protein has been widely used in recombinant protein expression and production. The fusion of the GST protein allows simple and efficient affinity purification of the GST-tagged protein using Glutathione affinity agarose resin. The GST-tag also can be used for detection in western blot by using a GST-tag-specific antibody. Scientists in KMD Bioscience are experienced in different types of protein purification services, we insist on providing high-quality CRO services, including information consultation, detailed experimental design and implementation.


GST Fusion Protein Purification Service Procedure:


2 His-tagged Protein Purification Service:

Many recombinant proteins are expressed as fusion proteins, meaning that they contain an affinity / epitope tag (e.g. His or GST). Histidine-tagged protein(Fig 1) purification uses affinity chromatography to capture recombinant proteins with 4–10 histidine residues. His-tagged proteins can be purified from several expression systems under native or denaturing conditions. The main drawback is that the technique often requires optimization to minimize nonspecific binding of host cell proteins. Protein binding capacity of resins is typically 10–40 mg/mL. The purity can be 95% or higher under KMD Bioscience’s lab.

Fig1 His tag fused to N or C terminus of recombinant proteins.


Histidine-tagged protein purification can be used as the only purification step for applications that do not require proteins with extremely high purity. Histidine-tagged protein purification can be used to purify inclusion bodies as well. His-tagged proteins can be purified by a single-step affinity chromatography, namely immobilized metal ion affinity chromatography (IMAC), which is commercially available in different kinds of formats, Ni-NTA matrices being the most widely used. IMAC purification can equally be performed in prepacked columns using FPLC or other liquid chromatography instrumentation, or using magnetic bead-based methods (Block et al., 2009). The histidine-tag is small, so it usually does not have to be removed.


Remove the tag if: it interferes with the function of the target protein or the target protein needs to be in a native state (e.g., for structural studies). Cleave the tag using a protease that recognizes the protease recognition sequence in the target protein. Some recombinant proteases are histidine-tagged, so they can be easily removed after a second pass over the resin used to purify the protein of interest.


All proteins purified by KMD Bioscience are analyzed by SDS-PAGE gel to determine the purity and integrity. All corresponding data will be provided to the customer. Other analysis methods can be available, please contact us today if you are interested in GST/His-tagged protein purification service.