Peptide glossary · Structure and synthesis
Aib (aminoisobutyric acid)
A non-proteinogenic amino acid with two methyl groups on the alpha carbon. It makes the neighbouring peptide bond hard to cleave. Semaglutide carries Aib at position 8 instead of alanine.
In the lab
Aib appears in several synthetic analogues to block breakdown at a specific position. In sequences it usually appears as "Aib" or "U".
Read moreData comparisonMore terms: Structure and synthesis
- AcetylationAdding an acetyl group, usually at the N-terminus.
- AmidationReplacing the C-terminal carboxyl group with an amide.
- AnalogueA molecule that resembles a natural model but is changed on purpose, for example by swapping amino acids or adding a side chain.
- C-terminusThe end of a peptide with the free carboxyl group, on the right of the sequence.
- D-amino acidThe mirror image of the natural L-amino acid.
- Deletion sequenceA synthesis by-product missing one or more amino acids.
For laboratory research use only. Not for use in humans or animals.