Body and drug basics
Fragment
Last updated
A fragment is a piece cut out of a longer chain: a stretch of the original amino acids, kept in their original order, with the rest left off. Fragments are usually named by the positions they cover, so a name with two numbers in it is telling you which slice of the parent molecule this is. The idea behind making one is that a short section might carry some of the parent's behaviour on its own.
Why it matters here
Fragment names look like the parent molecule's name with numbers bolted on, which makes it easy to assume the two are interchangeable. The record treats them as separate compounds, because a piece of a molecule is not the molecule.
What it is not
A fragment is not a smaller amount of the parent compound, and it is not guaranteed to do a subset of what the parent does. Cutting a chain can remove the part that mattered, leave the behaviour unchanged, or produce something that acts differently again.
Also called
- fragment
- fragments
- peptide fragment
- truncated peptide
- partial sequence
The numbers in a fragment's name are amino-acid positions counted from one end of the parent chain, marking where the slice starts and stops.
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.