The amino-acid sequence is the exact order of the building blocks in a chain, read from one end to the other. It is usually printed as a run of single letters or three-letter abbreviations, each standing for one amino acid. The order matters enormously, because it decides the shape the chain folds into and therefore what it is able to attach to.

Why it matters here

A sequence is the closest thing a peptide has to a fingerprint, and it is how you tell one compound from another with a confusingly similar name. Two products sold under the same marketing name but built to different sequences are different substances.

Also called

• amino acid sequence
• amino-acid sequence
• sequence
• peptide sequence
• primary structure
• one-letter code
• three-letter code

Also called the primary structure, meaning the order on its own, before any account of how the chain folds up.

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

• Amino acid — Body and drug basics
• Peptide — Body and drug basics
• Fragment — Body and drug basics
• Analogue — Body and drug basics