ChinaPeptides offers recombinant protein expression and purification to complement peptide and antibody programs. Hosts are selected according to folding, glycosylation and yield requirements. Purified proteins are supplied for research with project-specific documentation.
A useful inquiry includes the amino-acid sequence or accession, required tags, preferred host if you have one, and whether the protein will be used in an enzyme assay, structural work or as an immunogen. Peptide antigens for the same target can still be made by custom peptide synthesis when a linear epitope is the better immunogen.
Choosing a host
Protein expression typically starts with E. coli when the protein has no essential glycosylation. Yeast, insect and mammalian systems are discussed when folding or post-translational modification is part of the research question. The table on the expression page is a scoping aid, not a ranking.
- E. coli — intracellular, non-glycosylated targets; shortest typical path.
- Yeast — selected eukaryotic folding and some glycans.
- Insect — many intracellular or secreted research proteins.
- Mammalian — human-like secreted proteins when the assay needs that environment.
From construct to protein
Recombinant protein work covers construct review, expression testing and purification. Customers may provide plasmids or request construct design. Tag position (N- or C-terminal His, Fc or other) should be justified by purification and by the assay. Yield estimates before a test expression are not treated as commitments.
Protein purification is chosen from affinity, ion exchange, size exclusion and related methods. An ELISA antigen and a crystallography sample are not purified the same way. We document the steps that were actually run.
How a project is scoped
- Sequence and tag review.
- Host recommendation and optional test expression.
- Scale discussion based on the test, not on a guessed gram figure.
- Purification train matched to the research use.
- Buffer exchange and documentation.
Expression system comparison
The same four hosts are compared in detail on protein expression. Use that table when the inquiry is still choosing a system. This page is the cluster hub: host, construct and purification sit together so that a later quote does not contradict an earlier email.
| Host | Typical research use | Glycosylation | Relative timeline |
|---|---|---|---|
| E. coli | Intracellular, non-glycosylated targets | None (typical) | Shortest |
| Yeast | Selected eukaryotic folding | Selected glycans | Moderate |
| Insect | Many intracellular or secreted research proteins | Insect-type | Longer than bacteria |
| Mammalian | Human-like secreted proteins | Mammalian | Longest / highest cost |
Limits we will state
We do not promise enzymatic activity without an agreed assay. We do not invent instrument lists or headcount. Membrane proteins and highly toxic constructs need an explicit feasibility discussion. All proteins remain research materials.
Related reading on the peptide side remains useful when the same target also needs an epitope peptide: how to design a custom peptide and custom peptide synthesis.