Blog
The Proline Census: Which Catalog Peptides Are Rich in the Odd Amino Acid
Proline is unusual: its side chain loops back and bonds to its own backbone nitrogen. That removes a hydrogen bond donor and locks the angle of the chain, so proline acts like a built-in kink.
The count
| Peptide | Prolines | Length |
|---|---|---|
| Semax | 2 | 7 |
| BPC-157 | 4 | 15 |
| KPV | 1 | 3 |
| Melanotan-1 | 1 | 13 |
| DSIP, GHK, MT-2, Tesamorelin | 0 | 3 to 44 |
Why it matters
Proline-rich stretches resist forming helices, which tends to keep the peptide flexible and extended. The peptide bond before a proline can also flip between two shapes, cis and trans, and that interconversion is slow enough to produce double peaks in some analytical methods.
Nasal Semax ends in Pro-Gly-Pro, a tail also seen in other neuropeptide research. BPC-157 has a run of three prolines in a row near its front.
The opposite case
Tesamorelin has no prolines at all and 44 residues, which suits it to forming a helix when it binds its receptor. Different design, different shape.
- Proline-rich: flexible, resistant to helix formation.
- Proline-free long peptides: free to coil into helices.
- Watch for cis/trans split peaks on chromatograms.
Explore Lucid Aminos
- Shop all research compounds
- Read the lab reports (COA)
- Frequently asked questions
- Partner program
- About Lucid Aminos
- Contact us
For laboratory research use only. Not for human or veterinary use, and not intended to diagnose, treat, cure or prevent any condition. This article is educational and is not medical advice.