Common Peptide Sequences
Knowing the amino acid sequence of a peptide helps you verify its identity, understand its structure, and interpret mass spectrometry data on Certificates of Analysis. This reference lists the sequences of the most commonly researched peptides.
Key Takeaways
- Every peptide has a unique amino acid sequence that defines its identity and biological activity.
- Molecular weight from mass spectrometry should match the expected MW for the stated sequence.
- Sequence modifications (D-amino acids, fatty acid chains, cyclization) enhance stability and receptor affinity.
- Shorter peptides like GHK-Cu (3 amino acids) have simpler structures; longer ones like tirzepatide (39 amino acids) are more complex.
- Use these sequences to verify peptide identity against CoA mass spectrometry data.
Healing and Recovery Peptides
These peptides are researched for their potential to promote tissue repair, reduce inflammation, and accelerate recovery processes through various biological mechanisms.
- 1.BPC-157 (Body Protection Compound): Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val | 15 amino acids | MW: 1419.53
- 2.TB-500 (Thymosin Beta-4 fragment): 43-amino acid peptide, sequence Ac-SDKPDMAEIEKFDKSKLKKTETQEKNPLPSKETIEQEKQAGES | MW: ~4921
- 3.GHK-Cu (Copper peptide): Gly-His-Lys with copper ion | Tripeptide | MW: 403.93 (with copper)
Growth Hormone Secretagogues
These peptides stimulate the release of growth hormone from the pituitary gland through various receptor mechanisms. They are among the most popular research peptides for body composition and anti-aging studies.
- 1.Ipamorelin: Aib-His-D-2Nal-D-Phe-Lys-NH2 | 5 amino acids (includes non-standard) | MW: 711.85
- 2.CJC-1295 (no DAC): Tyr-D-Ala-Asp-Ala-Ile-Phe-Thr-Gln-Ser-Tyr-Arg-Lys-Val-Leu-Ala-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Leu-Ser-Arg-NH2 | 29 amino acids | MW: 3367.97
- 3.Sermorelin: Tyr-Ala-Asp-Ala-Ile-Phe-Thr-Asn-Ser-Tyr-Arg-Lys-Val-Leu-Gly-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Met-Ser-Arg-NH2 | 29 amino acids | MW: 3357.96
- 4.Tesamorelin: Modified GHRH analog, 44 amino acids with trans-3-hexenoic acid modification | MW: ~5135.9
GLP-1 Receptor Agonists
These peptides mimic or enhance the action of glucagon-like peptide-1, a hormone that regulates appetite and glucose metabolism. They represent some of the most clinically successful peptide therapeutics.
- 1.Semaglutide: Modified GLP-1 (7-37) with Aib at position 8, Arg at position 34, and C-18 fatty acid linker at Lys-26 | 31 amino acids | MW: ~4113.58
- 2.Tirzepatide: Dual GIP/GLP-1 receptor agonist, 39-amino acid peptide with C-20 fatty acid moiety | MW: ~4813.45
- 3.Liraglutide: GLP-1 (7-37) with Arg34 substitution and C-16 fatty acid at Lys-26 | 31 amino acids | MW: ~3751.2
Neuroprotective and Cognitive Peptides
These peptides are researched for their effects on cognitive function, neuroprotection, and neuroplasticity. Many are derived from or inspired by naturally occurring neuropeptides.
- 1.Semax: Met-Glu-His-Phe-Pro-Gly-Pro | Synthetic ACTH (4-10) analog | 7 amino acids | MW: 813.93
- 2.Selank: Thr-Lys-Pro-Arg-Pro-Gly-Pro | Synthetic tuftsin analog | 7 amino acids | MW: 751.90
- 3.Epitalon: Ala-Glu-Asp-Gly | Synthetic epithalamin fragment | 4 amino acids | MW: 390.35
Other Notable Research Peptides
These peptides do not fit neatly into the categories above but are commonly encountered in research contexts.
- 1.Melanotan II: Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2 | Cyclic heptapeptide | MW: 1024.18
- 2.AOD-9604: Modified GH fragment (176-191) with Tyr at N-terminus | 16 amino acids | MW: 1815.08
- 3.MOTS-c: Mitochondria-derived peptide, 16 amino acids: MRWQEMGYIFYPRKLR | MW: 2174.56
- 4.PT-141 (Bremelanotide): Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH | Cyclic heptapeptide | MW: 1025.18
Frequently Asked Questions
How do I verify that my peptide matches the expected sequence?
The primary verification method is mass spectrometry on the CoA. Compare the observed molecular weight to the expected weight for the sequence. A match within 0.1% confirms the peptide has the correct mass, which strongly suggests the correct sequence. Full sequence verification requires peptide sequencing techniques (Edman degradation or MS/MS), which are rarely included on standard CoAs.
Why do some peptides contain D-amino acids?
D-amino acids are mirror images of the natural L-amino acids found in biology. Including D-amino acids in a peptide sequence makes it resistant to enzymatic degradation because the body enzymes that break down peptides are specific to L-amino acid bonds. This extends the half-life and increases oral bioavailability in some cases.
What do modifications like Ac- and -NH2 mean in a peptide sequence?
Ac- (acetylation) at the N-terminus and -NH2 (amidation) at the C-terminus are common peptide modifications that protect the ends from enzymatic degradation. Acetylation neutralizes the positive charge at the N-terminus, and amidation neutralizes the negative charge at the C-terminus. Both modifications increase peptide stability and can enhance biological activity.