N-Acetyl Epitalon Amidate

1 Identity

Synthetic linear tetrapeptide, N-terminally acetylated and C-terminally amidated. Both termini capped; all four residues proteinogenic and L; no cysteine, no disulfide, no lipid, no PEG, no metal, no non-proteinogenic residue. and the two forms differ by 42.011 Da. which is ambiguous: used without "N-acetyl" it may or may not carry the N-terminal acetyl. and the vendor shorthand "Epitalon Amidate". The parent is Epitalon, also written Epithalon or AEDG peptide, H-Ala-Glu-Asp-Gly-OH, PubChem CID 219042, carried at its own record in the catalog. Not a synonym for Epitalon.

Sequence

Ac-L-Ala-L-Glu-L-Asp-Gly-NH2 (one-letter AEDG). Four residues. The acetyl site is unambiguous by construction: the only amine in the parent is the Ala1 alpha-amine, since Glu and Asp bear side-chain carboxylates and Gly has no side chain, so "N-acetyl" can only mean Ala1. The amidation site is where the ambiguity actually lives and it is analytical rather than nominal — the C-terminal glycine carboxyl, the Glu2 side-chain carboxyl and the Asp3 side-chain carboxyl are all candidates for amidation and all three products share one formula and one mass. Only MS/MS b-ion and y-ion assignment localizes it, so the amidation site is carried as a named attribute on the certificate: a certificate reporting intact mass alone has not tested it. Three chiral centers, at Ala1, Glu2 and Asp3; glycine is achiral.

Molecular formula

C16H25N5O9 (salt-free). Derivation: parent Epitalon C14H22N4O9; N-terminal acetylation +C2H2O; C-terminal amidation replaces the terminal hydroxyl with an amine, -O +NH. No independent supplier record corroborates the article as named; the identity stated here is two named transformations applied to the verified parent, PubChem CID 219042, and it is presented on that basis rather than on a supplier claim.

Average mass

431.402 Da, from C16H25N5O9 on IUPAC 2021 abridged conventional atomic weights (C 12.011, H 1.008, N 14.007, O 15.999). On the pre-2021 table the same formula returns 431.395; this catalog standardizes on the 2021 table and prints the basis. Reference points: parent Epitalon C14H22N4O9 average 390.349, which agrees with the widely published approximately 390.3 for the verified PubChem formula; N-acetyl Epitalon free acid C16H24N4O10 average 432.386; Epitalon C-terminal amide C14H23N5O8 average 389.365.

Monoisotopic mass

431.1652 Da neutral monoisotopic, from C16H25N5O9. [M+H]+ 432.1725; [M+2H]2+ 216.5899; [M-H]- 430.1580. Reference points: parent 390.1387; N-acetyl free acid 432.1492; Epitalon amide 389.1547. The two arithmetic facts that govern the specification are that this article sits exactly +41.0265 monoisotopic above the parent (acetyl +42.0106 combined with amidation -0.9840), and exactly -0.9840 below the N-acetyl free acid.

Salt / variant note

Four articles circulate under loose use of this shelf name and every pair is separated by arithmetic rather than by inspection. (1) The product: Ac-AEDG-NH2, C16H25N5O9, average 431.402 / monoisotopic 431.1652. (2) N-acetyl Epitalon free acid, Ac-AEDG-OH, C16H24N4O10, average 432.386 / monoisotopic 432.1492 — exactly +0.9840 above the product and invisible on a unit-resolution quadrupole. This is the single likeliest wrong molecule to pass a nominal-mass identity test on this record. (3) Epitalon amide, H-AEDG-NH2, C14H23N5O8, average 389.365 / monoisotopic 389.1547 — the des-acetyl species, -42.0106 from the product, and the cheaper article of the two. (4) Bare Epitalon, H-AEDG-OH, C14H22N4O9, average 390.349 / monoisotopic 390.1387 — sold more cheaply by essentially every peptide seller, which makes substitution here economic rather than accidental; it sits -41.0265 from the product. Beyond substitution, three isobaric species share the product's exact formula and cannot be separated by mass at any resolving power: the Glu2 side-chain amide and the Asp3 side-chain amide, both of which are what an unlocalized "amidate" can turn out to be, and the beta-aspartyl (isoaspartyl) rearrangement product at Asp3, which this sequence is prone to because Asp is followed by Gly — the fastest aspartimide-forming pair in peptide chemistry. The D-Asp3 epimer generated by the same ring-opening is likewise identical in formula and in both masses. Salt form is a further axis: acetate and trifluoroacetate are both plausible on a peptide with two free carboxylates in the parent, and gross weight does not equal peptide weight until the counterion is quantified. Also on this shelf and not to be confused: Vesugen (KED) and other short Khavinson-family peptides sit near 390 and 418 nominal and are indistinguishable from this family at nominal mass.

2 Class & testing panel

Form

Single article

Testing panel

P1 — panel definition

3 Primary sources & evidence

The index reports the design and provenance of the literature, not a conclusion about effect.

Published literature exists for the parent and essentially none was identified for this derivative. The parent's file is animal and in-vitro evidence only, and it carries a specific structural problem: the human evidence commonly cited belongs to a different, extract-based product rather than to the synthetic tetrapeptide, comes from a single non-blinded research lineage, and has never been independently replicated or registered. The primary literature is predominantly Russian-language, from the St. Petersburg Institute of Bioregulation and Gerontology lineage associated with Khavinson and Anisimov, and is largely rodent and cell-culture work from the 1990s and 2000s. For the N-acetylated C-terminally amidated derivative specifically, no primary publication, no registered trial and no pharmacopoeial monograph was identified. The citation index page for this record therefore says on its face that it is empty for the article as named, and that the parent's literature is not transferable to it, because a terminal modification changes the molecule.

4 Storage & specification

Storage

Lyophilized white to off-white solid in a Type I amber glass vial under nitrogen, stoppered and crimped. Store at -20 degrees C plus or minus 5 degrees C, desiccated over silica, protected from light and moisture; equilibrate the sealed vial to room temperature before opening. The article is hygroscopic and the label carries a close-immediately-after-weighing instruction; Karl Fischer is run at release and at every retest point. Ships ambient with a labeled cumulative excursion allowance of 120 hours at or below 30 degrees C, gel packs at 2 to 8 degrees C beyond that, and a single-use temperature logger in every export carton. Not stored reconstituted; the vial label and the certificate both say so.

Shelf life

Provisional 24 months at -20 degrees C plus or minus 5 degrees C from the date of QA release, stated as provisional pending this company's own stability data — nothing has yet been measured by this company. The confirming study is an ICH Q1A(R2) design with the isoaspartyl and succinimide species at Asp3-Gly4 as the stability-indicating attributes, alongside total related substances, des-acetyl species and water: 0, 3, 6, 9, 12, 18 and 24 months at -20 degrees C, with 2 to 8 degrees C and 25 degrees C / 60 percent relative humidity arms. Extension to 36 months only on real-time data at 18, 24 and 36 months. Printed retest date on every vial, first-expiry-first-out enforced against it. If the isoaspartyl limit is approached early, the interval shortens.