The gene for the protein is inserted into a host organism, commonly Escherichia coli, yeast, or a mammalian cell line, and the host's own machinery builds the chain. This is how proteins too long for practical chemical synthesis are made, which in this taxonomy means most things longer than about fifty amino acids. The host leaves its fingerprints: bacterial expression adds no sugar chains, and mammalian cells add ones that may not match the human pattern.

Why it matters here

Recombinant products bring their own quality questions, including host cell protein, endotoxin, correct folding, and whether any sugar chains match the native molecule. Those differ from the questions a chemically synthesised peptide raises, so origin is worth reading before a certificate of analysis.

Also called

• recombinant
• biosynthetic
• e coli expressed

E coli expressed names the commonest bacterial host. Biosynthetic is an older word for the same idea, and it is easily misread as bio-identical, which is a different claim.

Compounds carrying this term

None on file yet. This term is in the controlled vocabulary but no compound record currently uses it — which is a statement about our coverage, not about the term.

See also

• Synthetic — Molecular Origin
• Recombinant Protein — Compound Type
• Human Endogenous — Molecular Origin