Which host should I choose first?

E. coli is often first when glycosylation is not required. Yeast, insect and mammalian systems are discussed when folding or glycans are part of the assay.

Do you accept customer plasmids?

Yes, when the construct is documented. Tag position and antibiotic markers should be stated.

Is yield quoted before a test expression?

No. A test expression reports what that construct produces; scale is discussed afterward.

Protein Expression Host Systems

Protein expression projects are evaluated for solubility, tags, host compatibility and downstream purification. ChinaPeptides works with bacterial, mammalian, insect and yeast systems.

Small-scale expression tests can precede scale-up when the construct is unproven. That test is often the difference between a useful protein and a large pellet of inclusion bodies.

E. coli is typically fastest for intracellular, non-glycosylated targets. Yeast can add selected eukaryotic processing. Insect cells are used for many intracellular and secreted research proteins. Mammalian expression is discussed when authentic glycosylation or a human-like folding environment is required for the assay.

Host choice is a research decision, not a marketing ranking. A mammalian system is not “better” if the assay does not need mammalian glycans and the construct already expresses in E. coli. We will say when a cheaper host is the honest first test.

Customers may supply a plasmid or request codon optimization and gene synthesis as part of the same research project. Antibiotic markers, tag position and whether the protein is secreted should be written down before a test expression is started.

How we use the table

The comparison below is a scoping aid, not a ranking. The assay, glycosylation need and construct history choose the host.

Test expression before scale

An unproven construct should not jump to a large fermentation or culture. A small test reports soluble versus insoluble product, approximate yield and whether the tag is useful. Scale is discussed after that result, not before.

What we will not promise

We do not guarantee enzymatic activity without an agreed assay. We do not invent instrument lists or typical gram yields for unnamed proteins. Membrane proteins and highly toxic constructs need an explicit feasibility discussion.

Expression system comparison

Host	Typical 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

Protein Expression