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Proteogenix – Recombinant protein purification
Protein purification
The global growth in the need of recombinant protein expression and purification leads to the development of ever more ingenious strategies to improve yields, purity and quality of protein folding.
IMAC affinity chromatography
Purification methods used by Proteogenix are numerous and depend on the nature of protein, expression conditions and the chosen tag. Affinity chromatography known as “IMAC (Immobilized Metal Affinity Chromatography)” is yet the most widely used because it has the particular advantage of a strong and specific binding purification that allows the use of elution conditions less damaging to the integrity of the protein than other purification methods.
Tags for Recombinant protein purification
Purification is usually done by affinity against the tag whose choice depends on the nature of the protein. Proteogenix’ most commonly used tags are GST and histidine tags but it is also possible according to the context to use MBP, FLAG, HA, SUMO tags…
We usually use GST, MBP or SUMO tags, among others, to improve the solubility of proteins.
Ion exchange protein purification and cleavage
For clinical use, the presence of tags can be problematic and it is therefore interesting to choose ion exchange type purifications for example. Proteogenix also offers the ability to cleave tags used for purification but once again a large number of possibilities exist. Indeed, examining the context of expression and purification of the recombinant protein helps to decide to use an enterokinase cleavage (the cleavage site can be integrated during gene synthesis between the tag and the protein) followed by purification, or an on-column GST cleavage, among others. In the vast majority of cases it deals with recombinant endoproteases that recognize a specific sequence. Each option has advantages and drawbacks: some leave a few amino acids from the cleavage site, cleavage yields vary greatly …
The use of tags allows a relatively good purity, often above 90% although some tags, because of their greater specificity, can achieve better levels of purity than others.