Introduction for Three Kinds of Protein Labeling


Protein labeling is a peptides or protein that can combine with targeted proteins with the help of DNA recombination technology in order to pave the way for protein expression. Recently, these protein labeling are widely used in basic researches and commercial production.
This post will introduce the main three kinds of protein labeling and their advantages.


His6 refers to a combination label formed by six histidine residues. It can be inserted into the C-terminal or N-terminal of targeted proteins. It can be used in the IMAC. The advantages of this technology are as following:

1.Molecular weight is very light, which will not influence the function of targeted proteins.

2.His6 fusion protein can be purified under the nonionic surfactants condition.

3.His6 fusion protein is also being used in the researches of the protein-protein and protein-DNA interaction.

4.Immunogenicity of His is relatively low. So it can inject the purified proteins into animals to exert immune function and prepare antibodies.


Flag protein label is a peptide, which can be used to label eight amino acid. And the Kizak sequencing in the carrier can let the flag fusion protein express effectively. As a protein label, Flag protein label has following advantages:

1.Flag, as a fusion label, will not react with the targeted proteins and affect the nature and functions of targeted proteins. So it is possible for scientists to do the downstream research of fusion protein.

2.The targeted protein can access the FLAG to the chromatography process. This is also called non-denaturing purification, which is very efficient.

3.FLAG can be recognized by the its antibody. So it is very easy to detect and analyze the FLAG fusion protein with the help of Western Blot and ELISA.

4.Fused in N-terminal, FLAG can be removed by the DDDK to get the special targeted proteins. So the FLAG label has been widely used in protein expression, purification, identification, function research and protein-protein interaction.


eGFP is generated by the wild-type green fluorescent protein---GFP. Compared with GFP, eGFP has stronger fluorescence intensity and the stable fluorescence feature. eGFP has following advantages:

1.eGFP is also called live cell probe. Because it can emit green fluorescence through fluorescence microscopy directly without any help of crushing tissue cells.

2.Its fluores can help scientists to find out the targeted genes’ position in cells.

3.It will not interfere with the detection of protein label and it makes the process more simple and easy.

4.Because of the low consumption and high sensitivity, it is widely used in the drug screening

There are three kinds of protein labeling. Their advantages and workflow can help a lot in your researches.

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