Vilon

1 Identity

Base synthetic dipeptide. Two proteinogenic L-residues, free alpha-amino N-terminus, free C-terminal carboxyl, no acylation, no amidation, no cyclization, no cysteine, no disulfide, no metal, no non-proteinogenic residue. It is the simplest article in this catalog's short-peptide block. Charge state distinguishes it from its immediate neighbors and matters analytically: two carboxyl groups against two basic centers — the alpha-amino group and the lysine epsilon-amine — so it is close to zwitterionic at neutral pH, unlike the di-acid Vesilut on the same shelf. No aromatic residue, therefore no 280 nm chromophore. Supplied as the lyophilized free peptide or as the acetate or trifluoroacetate salt of one or both amines. The "cytogen" dipeptide of the Khavinson short-peptide program. A second registry number, 79443-38-8, also circulates for this article; the conflict is recorded here rather than settled in favor of the more common number.

Sequence

H-L-Lys-L-Glu-OH (KE). Two residues, both L, joined through the lysine alpha-carboxyl to the glutamate alpha-amino group. Free N-terminus, free C-terminal acid, no end-caps, no modifications, no disulfide. Three attributes fix this identity and none of them is A mass: the residue order (Lys-Glu, not Glu-Lys — the reversed dipeptide shares the formula and both masses exactly); the linkage, since coupling through the lysine epsilon-amine rather than the alpha-amine gives an isomer of identical formula; and the configuration, both L. Unlike most members of this series the trade-name-to-structure link here is not carried by vendor attribution alone: the sequence is stated under the trade name in indexed primary literature, and the CAS number 45234-02-4 is registered specifically to N-L-lysyl-L-glutamic acid, which fixes the order.

Molecular formula

C11H21N3O5 (free peptide). Salt forms carried as separate formula units: mono-acetate C13H25N3O7; mono-trifluoroacetate C13H22F3N3O7. With two basic centers a di-salt is possible and the stoichiometry is a stated attribute rather than an assumption. The formula is shared exactly by the reversed dipeptide Glu-Lys, by the epsilon-linked isomer and by every stereoisomer, so it is not an identity statement on its own.

Average mass

Average mass 275.305 Da (C11H21N3O5, free peptide), computed from the formula and independently reconstructed residue-by-residue from Lys plus Glu plus water; the two routes agree to the digit, and three external sources publish the same formula with MW 275.3. Salt forms: mono-acetate 335.357; mono-trifluoroacetate 389.327 — and on a 275 Da peptide a single trifluoroacetate counterion is 41 percent of the article's own mass. One live seller page prints C11H21N3O5 alongside "MW 257.30", a digit transposition of 275.30. It is recorded here as found, and as a warning about vendor arithmetic in this series: a supplier that cannot transcribe a molecular weight is not a supplier whose identity claims can be taken on trust.

Monoisotopic mass

275.14812 Da neutral (C11H21N3O5). Working ions: [M+H]+ m/z 275.15540, [M-H]- m/z 274.14084, [M+Na]+ m/z 297.13734. A plus or minus 5 ppm window on the neutral is plus or minus 0.0014 Da. That window is trivially met and excludes almost nothing on its own, because the molecules that matter here — the reversed dipeptide, the epsilon-linked isomer and the stereoisomers — share the figure exactly at every decimal place and at every resolving power. Mono-acetate 335.16925; mono-trifluoroacetate 389.14098; pyroglutamate-type cyclization product C11H19N3O4 257.290 / 257.13756, exactly minus 18.011 Da.

Salt / variant note

The isomers that no mass measurement separates, all C11H21N3O5 at 275.14812 exactly. (1) GLU-LYS, the reversed dipeptide: identical formula, identical average mass, identical monoisotopic mass, distinguishable only by an assigned b/y ion series, by Edman, or by co-elution against two named standards. (2) the epsilon-linked isomer, in which the glutamate is coupled to the lysine side-chain amine rather than to the alpha-amine: same formula, same mass, and the direct product of inadequate side-chain protection during synthesis. (3) the stereoisomers at either center. Four candidate molecules stand behind a single accurate mass, which is why this record's certificate requires three orthogonal identity results rather than one. Mass-resolvable neighbors, each computed from its formula: Lys-Asp C10H19N3O5, 261.278 / 261.13247, minus 14.03 Da; Lys-Gln C11H22N4O4, 274.321 / 274.16411, minus 0.98 Da and the amide read backwards; Arg-Glu C11H21N5O5, 303.319 / 303.15427; the cyclization product at C11H19N3O4, 257.290 / 257.13756, minus 18.011 Da; free L-Lys 146.190 / 146.10553 and free L-Glu 147.130 / 147.05316, the unreacted starting materials. Salt forms: mono-acetate 335.357, mono-trifluoroacetate 389.327; one trifluoroacetate is 41 percent of the peptide's own mass and a di-salt is possible on two basic centers. Same-family articles sold from the same page at the same 20 mg size, each with its own derived mass: Vesilut ED C9H14N2O7 262.218 / 262.08010; Chonluten EDG C11H17N3O8 319.270 / 319.10156; Cartalax AED C12H19N3O8 333.297 / 333.11721; Thymagen and Thymogen EW C16H19N3O5 333.344 / 333.13247; Ovagen EDL C15H25N3O8 375.378 / 375.16416; Epitalon AEDG C14H22N4O9 390.349 / 390.13868; Vesugen KED C15H26N4O8 390.393 / 390.17506; Pinealon EDR C15H26N6O8 418.407 / 418.18121; Testagen KEDG C17H29N5O9 447.445 / 447.19653; Livagen KEDA C18H31N5O9 461.472 / 461.21218. Two name-level traps that arithmetic cannot reach: "Normophthal", which at least one seller prints as an alternative name on its Vilon page and which this catalog carries as a separate record with its sale closed, precisely because no published sequence exists for it; and the Cytomax tissue-extract preparations, sold under the same brand lineage by the same sellers, which have no mass at all and against which no substitution can be proved in the correct direction.

2 Class & testing panel

Form

Single article

Testing panel

P1 — panel definitionFour molecules share 275.14812 exactly, so accurate mass is corroboration on this article rather than proof. The certificate carries three orthogonal identity results instead: an assigned b/y ion series, a chromatographic result against a characterized standard, and a chiral result

3 Primary sources & evidence

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

Literature exists and is recorded by study type with no statement of effect. This is one of the few members of the Khavinson series named in primary work rather than only in the program's reviews: Khavinson VK and Kvetnoii IM, Bull Exp Biol Med 2000, PMID 11276315, rat study, in which this dipeptide and Epitalon are the articles examined; Avolio F et al., Int J Mol Sci 2022, PMID 35408963, DOI 10.3390/ijms23073607, in-vitro human THP-1 monocytic cell line, internationally co-authored between Italian universities and the Saint Petersburg institute, in which this dipeptide is one of five preparations evaluated; and an indexed rodent study by Anisimov and colleagues whose title names the article as "a synthetic dipeptide vilon (L-Lys-L-Glu)", cited here for the name-to-structure link rather than for its findings. The article is also among those covered by the group's 2013 clinical-studies review, PMID 24003726, which is a review by the originating group and not a primary randomized trial. Program-level citations: PMID 12374906, review; PMID 31808038, review and the source of the class's verbatim structural claim; PMID 23734519, review of experimental work; PMID 32593244, review. The class carries an evidence grade of D — animal and in-vitro work plus non-independent, largely Russian-language reviews from the originating institution, with no independently replicated randomized human trial located, across roughly 160 publications spanning 1993 to 2025 dominated by one institution and one author group. No ClinicalTrials.gov registration was identified and no NCT number is quoted because none was found. No marketing authorization in the United States. The research page carries the field's objection to the program's central structural claim: a dipeptide has too few contacts to specify a unique genomic site, and no independent replication by an unaffiliated laboratory was located.

4 Storage & specification

Storage

Lyophilized white to off-white powder in the sealed original container with in-pack desiccant, protected from light. Labeled storage -20 degrees C plus or minus 5 degrees C, desiccated; 2-8 degrees C is acceptable for transit and for working stock held no longer than 30 days, and the in-use stability study brackets that condition. The material is strongly hygroscopic, which on a 275 Da article is a specification matter rather than a handling nicety: condensation onto a cold cake moves the water figure enough to move the net peptide claim, and the net peptide claim is the label. Vials are equilibrated to room temperature sealed before opening. Reconstituted aqueous solutions are refrigerated and used promptly; a dipeptide with free termini is substrate for any residual amino- and carboxypeptidase activity in a biological matrix, which is an experimental-design consideration for the buyer and is stated as such rather than as a property of the article. Shipping validation covers a 72-hour excursion to 25 degrees C.

Shelf life

Provisional 36 months at -20 degrees C plus or minus 5 degrees C in the sealed original container, assigned by protocol and not measured, pending this company's own ICH Q1A-format long-term and accelerated data on the first three lots. The interval sits above the 24-month house default because the molecule has no oxidation-labile residue — no Met, no Trp, no Cys — no aromatic residue, no disulfide and no aspartyl-glycine motif; and because its N-terminus is lysine rather than glutamate, it does not carry the pyroglutamate route that dates the Glu-initiated members of the same family. The attributes to trend are water content, counterion stoichiometry and the minus 18.011 Da cyclization species, not gross purity; the stability-indicating method must be demonstrated to resolve that species from parent before the first lot is placed on stability. Shortened on data, never extended without a completed dataset.