The Protein Man's Blog | A Discussion of Protein Research

Agarose beads are small spherical beads of agarose gel which are commonly used in gel filtration or molecular size exclusion chromatography and biomolecular purification and immobilization. These beads act as porous gel to filter mixtures of molecules based on their individual sizes. And since these beads are easy to activate, they can also be used to bind biomolecules in a reversible or irreversible manner. In addition, their inert nature and unique internal surface area can also be activated for ligand attachment, making them the ideal basis for various affinity chromatography beads such as protein A and G, and glutathione.

Tagging your protein of interest can be extremely useful since it simplifies the purification protocol, improves the yield and solubility of your protein of interest and promotes the proper folding of their fusion partners. Due to their versatility, affinity tags (peptide sequences that are appended to the target protein) are recognized as one of the most powerful tools that can be used for basic biological research and in structural and functional proteomics as well.

Since 1975, immobilized metal affinity chromatography (IMAC) has been popularly used in purifying proteins, especially those that are fused to a polyhistidine tag, typically a 6X His tag. This process gained immense popularity since it allows for the efficient purification of proteins, even those from crude lysates. In addition, its robust nature makes it ideal for methods that require protein-specific conditions. Its functional simplicity, affordability and compatibility with a wide range of reagents also add to its popularity.

Basically, protein tags are peptide sequences that are attached to proteins to facilitate easy detection and purification of expressed proteins. In addition, they can also be used to identify potential binding partners for your protein of interest.