A peptide sequence is the specific order of amino acids in a peptide, written from the N-terminus (the amine end) to the C-terminus (the acid end). The sequence determines the peptide's shape, identity, and function.
What the sequence describes
Every peptide is a chain of amino acids. The sequence is simply the roster of which amino acids appear and in what order. By convention it is read in one direction, from the N-terminus to the C-terminus, so that the same peptide is always described the same way.
How sequences are written
Because writing out full amino acid names would be cumbersome, chemists use short codes:
- Three-letter codes: for example Gly-His-Lys.
- One-letter codes: the same peptide written as GHK.
That example, GHK, is a real tripeptide better known as the copper peptide GHK-Cu when bound to copper.
Browse research-grade peptides
Every Axis compound is third-party tested to 99.4%+ purity, with a certificate of analysis on every batch.
Why sequence is everything
A peptide's sequence dictates how it folds and which receptors it can bind. Rearrange the order, swap one amino acid, and you can get a molecule that behaves completely differently. This is why identity is a sequence question, and why reputable suppliers verify the sequence of every batch before it ships. The proof lives on the certificate of analysis.
Key takeaways
- A peptide sequence is the order of amino acids, read N-terminus to C-terminus.
- Sequences are written in one-letter or three-letter amino acid codes.
- The sequence determines the peptide's shape, identity, and function.
- Verifying the sequence is how a peptide's identity is confirmed.
A note on research use
The peptides supplied by Axis Peptide Labs are reference compounds for laboratory and research use only. They are intended for qualified researchers working in academic, institutional, and analytical settings. They are not drugs, foods, cosmetics, or medical products, and they are not intended for human or veterinary consumption. Documented identity and documented purity are what matter most when sourcing a compound, both of which are published on the Axis certificates of analysis page.
