Body and drug basics
Peptide
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A peptide is a short chain of amino acids, which are the small building blocks living things use to make proteins. Picture beads threaded on a string: each bead is one amino acid, and a peptide is a short strand of them, conventionally anything from two up to about fifty. Most peptides act as messengers, carrying an instruction from one part of the body to another, rather than doing structural work.
Why it matters here
Every compound record on this site is filed under exactly one type, and Peptide is only one of them. Plenty of things sold as peptides are not peptides at all, so the type line on a record tells you what you are actually looking at before any claim about it does.
What it is not
Not everything marketed as a peptide is one. The word is used commercially for small molecules, vitamin cofactors, polynucleotides and exosome preparations, none of which are chains of amino acids. This site also carries Peptide as a Compound Type entry, which is the filing rule used to sort products; this entry is the plain-language explanation of what the word means. The fifty-amino-acid ceiling in both is a convention fixed for consistency, not a fact of chemistry.
Also called
- peptide
- peptides
- polypeptide
- oligopeptide
- peptide chain
Polypeptide usually means a longer chain and oligopeptide a very short one, but the words are used loosely and often interchangeably.
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.