Peptide reference · Amidated decapeptide
Kisspeptin-10 COA check: molecular weight, formula and what to look for
Use these reference values to check the identity result on a Kisspeptin-10 Certificate of Analysis. The theoretical average molecular weight of Kisspeptin-10 is 1,302.44 Da and the monoisotopic mass is 1,301.630 Da.
Check a Kisspeptin-10 COA nowKisspeptin-10 reference data
| Name | Kisspeptin-10 |
|---|---|
| Also known as | Metastin (45-54), KP-10 |
| Type | Amidated decapeptide |
| Molecular formula | C63H83N17O14 |
| Average molecular weight | 1,302.44 g/mol (Da) |
| Monoisotopic mass | 1,301.6305 Da |
| Residues | 10 |
| Sequence | Tyr-Asn-Trp-Asn-Ser-Phe-Gly-Leu-Arg-Phe-NH₂ |
| Reference source | PubChem CID 25240297 (formula and mass cross-checked) |
Expected mass spectrometry ions
A Kisspeptin-10 COA may list one of these m/z values instead of the neutral mass. That is still consistent with Kisspeptin-10. How charge states work.
| Ion | m/z (monoisotopic) | m/z (average) |
|---|---|---|
| [M+H]+ | 1,302.64 | 1,303.45 |
| [M+2H]2+ | 651.82 | 652.23 |
| [M+3H]3+ | 434.88 | 435.15 |
What else can show up on a Kisspeptin-10 COA
Masses calculated from Kisspeptin-10's formula and sequence for the adducts, degradation products and synthesis impurities a lab report can show. A match tells you what the extra peak probably is.
| Signal | Value | What it means |
|---|---|---|
| Na adduct, deconvoluted (M + 21.98) | 1,323.61 Da | Sodium adduct: an MS artifact, not a separate impurity. The [M+Na]+ ion itself is at M + 22.99 |
| K adduct, deconvoluted (M + 37.96) | 1,339.59 Da | Potassium adduct: an MS artifact. The [M+K]+ ion itself is at M + 38.96 |
| TFA adduct (M + 113.99) | 1,415.62 Da | Trifluoroacetic acid from purification seen as an adduct; residual TFA salt is real vial content |
| M + 16 (oxidation) | 1,317.63 Da | Oxidation of Trp |
| M + 0.98 (deamidation) | 1,302.61 Da | Asn/Gln deamidation; overlaps the natural isotope peak, needs high-resolution MS |
| M + 0.98 (free acid) | 1,302.61 Da | C-terminal amide hydrolysed or free-acid synthesis error |
Deletion sequences (8): one residue missing
| Signal | Value | What it means |
|---|---|---|
| des-Tyr (M − 163.06) | 1,138.57 Da | Deletion sequence missing one Tyr |
| des-Asn (M − 114.04) | 1,187.59 Da | Deletion sequence missing one Asn |
| des-Trp (M − 186.08) | 1,115.55 Da | Deletion sequence missing one Trp |
| des-Ser (M − 87.03) | 1,214.60 Da | Deletion sequence missing one Ser |
| des-Phe (M − 147.07) | 1,154.56 Da | Deletion sequence missing one Phe |
| des-Gly (M − 57.02) | 1,244.61 Da | Deletion sequence missing one Gly |
| des-Leu/Ile (M − 113.08) | 1,188.55 Da | Deletion sequence missing one Leu/Ile |
| des-Arg (M − 156.10) | 1,145.53 Da | Deletion sequence missing one Arg |
Adduct rows are deconvoluted masses (the shift seen against [M+H]+); the singly charged [M+Na]+ ion itself sits at M + 22.99. Deletion masses alone can't say which copy of a repeated residue is missing.
Short peptides like Kisspeptin-10 (10 residues) are easy to make cleanly, so 98% HPLC purity should be the floor, not the goal. The full checklist is in how to read a peptide COA.
Kisspeptin-10-specific things to watch
Kisspeptin-10 is the C-terminal decapeptide of kisspeptin with an amide end, about 1302.4 Da.
The C-terminal amide matters: the free-acid version would be about 1 Da heavier. A precise mass helps confirm the correct form.
Expect [M+H]⁺ near 1302.6 m/z and [M+2H]²⁺ near 651.8 m/z.
Kisspeptin-10 has one tryptophan, so a +16 Da peak (near 1,318.5 Da average) signals oxidation. Its two asparagines can each deamidate (+0.98 Da per site), which a low-resolution instrument can't separate from the normal isotope pattern.
A free C-terminal acid is also 0.98 Da heavier, the same shift as a deamidated asparagine, so even a precise intact mass can't tell those two apart. A precise monoisotopic mass (1,301.63 Da) is the most direct check for the amidated form; MS/MS or running a reference standard alongside the sample settles it.
Compounds with similar mass
If a COA's mass is off, compare it with these neighbors. A match to one of them can point to a mislabeled product.
- BPC-157: 1,419.54 Da (+117.10 Da)
- PT-141: 1,025.16 Da (-277.28 Da)
- Melanotan II: 1,024.18 Da (-278.26 Da)
Sources
- PubChem CID 25240297: Kisspeptin-10 formula and reference mass.
- CIAAW: Standard atomic weights: Used to calculate average molecular weights.
- NIST CODATA: proton mass: Used to convert m/z charge states to neutral mass.
- PeptideCOACheck methodology: How the checker's thresholds work.
Last updated . Written and maintained under our editorial policy. Found an error? See corrections.
Frequently asked questions
What does 651.8 m/z mean on a Kisspeptin-10 COA?
The [M+2H]2+ ion of the 1,301.6 Da (monoisotopic) molecule.
What does a Kisspeptin-10 peak near 1,318 Da mean?
Oxidized tryptophan (+16 Da).
How do I know Kisspeptin-10 has its C-terminal amide?
A precise monoisotopic mass of 1,301.63 Da is the most direct check. A result near 1,302.61 Da could be the free acid or a deamidated amide, which MS/MS or a reference standard can tell apart.
For laboratory research use only. This page describes analytical chemistry data. It is not medical advice and makes no claim about effects in humans or animals.