Human Proteins, Human Source™
Symansis' hcx proteins mimic the proteins in the human body because they are expressed from human, rather than animal, insect or bacterial cells. This process gives them human post-translational modifications.
| DNA | Expression System | rh Protein |
|---|---|---|
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| Proteins expressed in E. coli don't have some PTMs such as glycosylation | ||
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| Symansis' hcx™ proteins have human PTMs making them more human | ||
Recombinant DNA techniques allow a human protein with the correct amino acid sequence to be expressed in a non-human cell line. However, non-human cells lack the appropriate cellular machinery, such as specific glycosyltransferases, necessary to produce the correct human post-translational modifications of a protein. An extreme example is seen in E. coli cells, which produce recombinant proteins with no glycosylation, as the above figure illustrates.
Rodent and yeast cells are able to glycosylate proteins, but they are still different from glycosylation in human cells.
| Expression System | Resultant Proteins |
| Human (e.g. K562, HEK293) |
Correct amino acid sequence Human post-translational modifications |
| Rodent (e.g. CHO, NSO) |
Correct amino acid sequence Some natural glycosylation - not human-like |
| Yeast (e.g. Pichia) |
Correct amino acid sequence Some natural glycosylation - not human-like |
| E.Coli | Correct amino acid sequence No PTMs |
Although there have been significant attempts to make non-human cell derived cytokines more human-like, there is a growing awareness that in many instances, particularly in therapeutics, cytokines should mimic those found in the body as closely as possible.
This key difference can affect your research and applications:
- In in vitro experiments
- quantitation (ELISA)
- stability
- protein interactions
- Predicting effects in humans
- immunogenicity
- half life