Livagen Peptide (KEDA): Sequence, CAS, Molecular Weight and Mass Spec

Livagen peptide is the synthetic linear tetrapeptide H-Lys-Glu-Asp-Ala-OH (one-letter code KEDA), formula C18H31N5O9, average molecular weight 461.47 g/mol and monoisotopic mass 461.21 Da. PubChem records it as CID 87919683, titled Livagen, and lists CAS 433257-50-2 among the synonyms for that record; a second number, CAS 195875-84-4, is sometimes given for Livagen online, but PubChem resolves that number to an unrelated non-peptide compound. On a mass-spectrometry report, Livagen appears as the protonated ion [M+H]⁺ at a calculated m/z of 462.2. Pepta Labs lists it as a supplier-stated 20 mg of lyophilized powder per sealed glass vial on the Livagen 20mg listing.

What is the sequence, formula and molecular weight of Livagen?

Livagen is H-Lys-Glu-Asp-Ala-OH: four L-amino acids joined by three peptide bonds, with a free amine at the N-terminus and a free carboxylic acid at the C-terminus. Its molecular formula is C18H31N5O9 and its average molecular weight is 461.47 g/mol. These are the identity figures a certificate, a registry record or another listing should match.

Which amino acids make up KEDA?

KEDA is the one-letter code for Lys-Glu-Asp-Ala, read from the N-terminus to the C-terminus. With the free N-terminal amine, the lysine side-chain amine, two acidic side chains and the free C-terminal acid, the molecule is zwitterionic at neutral pH. The peptide sequence notation guide explains one-letter and three-letter codes and the H- and -OH terminal marks.

The formula can be checked by hand. The four free amino acids sum to C18H37N5O12; forming three peptide bonds removes three molecules of water (H6O3), leaving C18H31N5O9. The "H-" and "-OH" in H-Lys-Glu-Asp-Ala-OH mark the unmodified termini: no acetyl cap and no C-terminal amide.

Why does Livagen have two CAS numbers?

Livagen has one CAS number in PubChem, 433257-50-2; the second number sometimes given for it, 195875-84-4, belongs to a different compound. As checked on PubChem on 2026-09-24, CAS 433257-50-2 resolves to CID 87919683, the tetrapeptide Lys-Glu-Asp-Ala with formula C18H31N5O9, while CAS 195875-84-4 resolves to CID 11370864, a non-peptide small molecule with formula C17H23Cl2NO and a molecular weight of 328.3 g/mol. The two records share no formula, no mass and no structure, so only 433257-50-2 can describe Livagen.

Values are from PubChem compound records as retrieved on 2026-09-24. PubChem rounds molecular weight to one decimal place; the listing value for Livagen, 461.47 g/mol, rounds to the same 461.5.

A mismatched CAS number is a transcription problem, not a second form of the peptide. Salt forms and stereoisomers can carry their own CAS numbers, but they keep the peptide's formula or a close variant of it; a number whose record has chlorine atoms and no amide bonds cannot be a Livagen salt. When a certificate, listing or summary gives Livagen as CAS 195875-84-4, compare the formula and mass instead: C18H31N5O9 and 461.47 g/mol follow directly from the sequence, and a CAS number can be mistyped or copied from the wrong record.

What mass should a Livagen mass spectrometry report show?

A Livagen mass spectrum in positive electrospray mode should show the protonated molecule [M+H]⁺ at a calculated m/z of 462.2. That value is the monoisotopic mass of C18H31N5O9, 461.21 Da, plus one proton (1.0073 Da). The observed mass for the sampled production run is the value printed on the report.

All values are calculated from the formula with monoisotopic atomic masses, not measured. Most reports print one observed ion, usually [M+H]⁺. A sodium adduct 22 units above it is common in electrospray spectra and does not indicate a different compound. For a molecule this small the singly charged ion is normally the main peak, and a triply charged ion is rarely seen.

The expected mass table lists the same calculation for the catalog compounds whose identity records are verified, and HPLC vs mass spec explains what each instrument can and cannot show.

How do Livagen and epitalon differ in sequence and mass?

Livagen and epitalon are different compounds: Livagen is Lys-Glu-Asp-Ala (KEDA, C18H31N5O9, 461.47 g/mol) and epitalon is Ala-Glu-Asp-Gly (AEDG, C14H22N4O9, 390.35 g/mol). Both are synthetic linear tetrapeptides with free termini, and both carry Glu-Asp at positions 2 and 3; they differ at the first residue (lysine vs alanine) and the last residue (alanine vs glycine). Pepta Labs lists epitalon as Epithalon 10 mg.

The formulas differ by C4H9N, which is 71.12 g/mol on the average scale and 71.07 Da on the monoisotopic scale, so a mass spectrum separates the two at once: [M+H]⁺ at 462.2 is Livagen and 391.1 is epitalon. Epitalon formula and molecular weight are the values shown on the Epithalon listing.

What salt form is Livagen supplied as?

Each Livagen vial holds a supplier-stated 20 mg of lyophilized powder in a sealed glass vial, typically as an acetate or trifluoroacetate salt. The TFA vs acetate guide explains why the salt form changes how much of the stated mass is peptide; net peptide content is not reported per listing. Vial labels identify the compound, quantity and research-use designation. They do not carry lot or batch numbers.

Where are the Livagen listing, report and storage details?

Price, pack options, the analytical report and storage each have one owner page, and this reference links to them rather than repeating them.

• Price and packs: the Livagen 20mg listing shows the single-vial price and the 3-vial and 5-vial packs before checkout. The price per mg comparison sets Livagen beside the other listings.
• Analytical report: Independent third-party HPLC purity analysis and mass-spectrometry identity confirmation, commissioned through the purchasing group on a sampled production run from the source. Pepta Labs does not test in-house. The listing shows the RP-HPLC purity figure reported for the sampled production run. Ask for the report through the report request form, and use the COA verification guide to check the observed mass against 462.2.
• Storage: sealed vials are kept at 2-8 C short term or -20 C long term, dry and protected from light; the peptide storage guide covers lyophilized powders in detail.
• Shipping and returns: see the shipping terms and returns terms.

For how Livagen fits among the other listed compounds, start with what research peptides are, and for the same identity data across the catalog see the CAS numbers and molecular weights reference.

Frequently asked questions

What is Livagen peptide?

Livagen is the synthetic linear tetrapeptide H-Lys-Glu-Asp-Ala-OH (KEDA), formula C18H31N5O9, molecular weight 461.47 g/mol, recorded in PubChem as CID 87919683 with CAS 433257-50-2 among its synonyms. Pepta Labs lists it as a lyophilized laboratory reference material, not for human or animal use.

Is Livagen the same as KEDA?

Yes. KEDA is the one-letter amino-acid code for Lys-Glu-Asp-Ala, the sequence of Livagen: K for lysine, E for glutamic acid, D for aspartic acid and A for alanine, read from the N-terminus.

Why does Livagen have two CAS numbers?

It does not: PubChem links only CAS 433257-50-2 to Livagen (CID 87919683, C18H31N5O9). The other number seen online, CAS 195875-84-4, resolves in PubChem to CID 11370864, an unrelated non-peptide compound with formula C17H23Cl2NO (checked 2026-09-24).

What does CAS 433257-50-2 identify?

CAS 433257-50-2 is recorded in PubChem CID 87919683 for the tetrapeptide H-Lys-Glu-Asp-Ala-OH, formula C18H31N5O9, molecular weight 461.47 g/mol. The Pepta Labs listing shows no CAS number and identifies the compound by formula and molecular weight.

What mass confirms Livagen on a report?

The calculated [M+H]+ ion for Livagen is m/z 462.2, from a monoisotopic mass of 461.21 Da; a sodium adduct, if printed, sits at 484.2. The observed mass for the sampled production run is the value printed on the report.

Is Livagen the same compound as epitalon?

No. Livagen is Lys-Glu-Asp-Ala (C18H31N5O9, 461.47 g/mol) and epitalon is Ala-Glu-Asp-Gly (C14H22N4O9, 390.35 g/mol). They share Glu-Asp at positions 2 and 3 but differ at both ends, so their formulas, masses and registry records differ.

All products are supplied for laboratory research use only and are not for human or animal use.