Vilon research peptide: sequence and published literature

What Vilon is

Vilon is a synthetic 2-residue peptide whose sequence corresponds to the dipeptide L-lysine and L-glutamic acid, written Lys-Glu. In the single-letter amino-acid code that reads as KE, which is why the research literature commonly calls the molecule the KE peptide. The catalogue lists it in the cell-biology section and records no other catalogue synonyms for it.

The compound belongs to the group of very short synthetic peptides usually described as peptide bioregulators, a class defined in the Russian-language gerontology literature of the late twentieth century and studied there as a family rather than one molecule at a time. Peptides in that group are two to four residues long, are prepared by ordinary chemical synthesis rather than isolated from tissue, and are examined on the premise that a short peptide can interact directly with DNA and chromatin. Vilon is the two-residue member of the family most often paired with Epithalon in comparative gene-expression work, and the two frequently appear in the same publication.

At two residues the molecule is a small, highly polar organic compound with a single peptide bond. One side chain is basic, the epsilon-amino group of lysine, and one is acidic, the gamma-carboxyl of glutamic acid, so the dipeptide is zwitterionic across most of the ordinary buffer range and dissolves readily in aqueous media. It has no secondary structure. Vilon is supplied strictly as a laboratory research material and is not for human or veterinary use, nor for consumption, administration, diagnostic use or therapeutic use.

Structure and identifiers

The sequence is Lys-Glu, a linear dipeptide with a free N-terminal amine on the lysine residue and a free C-terminal carboxyl on the glutamic-acid residue. No acetylation, amidation, D-amino acid substitution or other modification is recorded for the catalogue material, and none is asserted here. Beyond the backbone the molecule carries three ionisable groups: the lysine side-chain amine, the glutamic-acid side-chain carboxylate and the two chain termini.

The catalogue entry records no numerical identifiers for this material. A CAS registry number is not catalogued here, a molecular formula is not catalogued here, and a molecular weight is not catalogued here, so none of the three is stated on this page. The sequence above is the identity information the entry carries, and the certificate of analysis issued with each lot reports the mass measured for that lot, which is the appropriate numerical reference for identity work.

The material is offered in a single 20 mg vial format and is supplied lyophilized. Lyophilized peptides of this type are handled as dry solids until they are reconstituted in an appropriate laboratory diluent.

What the published literature has examined

Published work has examined Vilon in cultured human lymphocytes, cultured monocytic cell lines, rodent tissue and tissue-explant models within gerontology, gene-expression research and cell biology. The papers listed on this page are bibliographic references only; they are not evidence of safety or efficacy and describe laboratory findings, not any use in people or animals.

The reference set for this material is small, dated mostly between 2000 and 2004, and largely Russian in origin. Several of the papers appeared in Bulletin of Experimental Biology and Medicine or in Advances in Gerontology, and one of those reaches the international indexes only through a translated title, so the field context is the peptide-bioregulator programme rather than mainstream molecular biology. Vilon rarely appears alone in this literature: it is studied next to Epithalon in the gene-expression papers and next to a cytostatic comparator, cyclophosphane, in the explant work.

The model systems in the reference set fall into three groups. The first is transcript profiling in animal tissue, using DNA-microarray technology applied to mouse heart to survey gene expression across many transcripts at once. The second is cultured human cells, including lymphocyte cultures taken from older donors and examined for chromatin state, an approach that reads condensed and decondensed chromatin fractions cytogenetically rather than by sequencing. The third is rodent and explant work: transplantable tumour models and lymphoid-tissue explants from mice and rats of different ages, and enzyme-activity measurement in the epithelial and subepithelial layers of small intestine in old rats. Alongside those references, the catalogue description names further measured variables examined in short-peptide work of this kind, including interleukin-2 expression in lymphocytes and the expression of regulatory proteins such as SIRT1, PARP1 and PARP2, and in-vitro models of inflammatory and proliferative response built on human monocytic cell lines.

Methods that recur across this body of work therefore include DNA-microarray hybridisation and its associated normalisation, cytogenetic and microscopic assessment of chromatin, organ and tissue explant culture, enzyme-activity assays on tissue homogenates or histological sections, and standard rodent lifespan and biological-age study designs. This paragraph and the two before it describe fields, models, measured variables and methods only. No result, endpoint value or comparison from any of the cited studies is stated on this page, and none of them establishes safety or efficacy for any use.

Storage and handling as a laboratory reagent

No compound-specific storage rows are recorded in the catalogue entry, so the general handling profile for lyophilized research peptides applies. In lyophilized form the vial is held at -20 C, protected from light, and kept sealed until it is opened in the laboratory. Allowing a cold vial to reach room temperature before it is opened keeps condensation from forming on the dry solid, which matters for a small, highly polar peptide that takes up atmospheric moisture readily.

Once reconstituted, the material is a short-lived laboratory reagent rather than a stock. Reconstituted solutions are held refrigerated at 2 to 8 C for short-term laboratory use, kept out of direct light, and protected from repeated freeze-thaw cycling, which is a common cause of drifting concentration in peptide work. Dividing a reconstituted solution into single-use aliquots at the point of reconstitution avoids warming the whole volume more than once.

Concentrations are worked out before diluent goes into the vial. The reconstitution calculator converts a vial mass and a target concentration into a diluent volume, and bacteriostatic water is the diluent most commonly catalogued for laboratory vials that will be entered more than once.

Analytical verification

Identity and purity for this material are established analytically. Purity is assessed by third-party reverse-phase HPLC, where the chromatogram separates the target peptide from synthesis-related species such as incompletely deprotected intermediates and single-residue impurities, and purity is reported as the target peak area relative to the total integrated peak area. A dipeptide is a demanding case for reverse-phase separation, since it is small and polar and elutes early, close to the void volume, which is why the identity check by mass spectrometry carries as much weight here as the chromatographic one. Identity is assessed against the expected molecular weight for the Lys-Glu sequence. A certificate of analysis is issued for each lot, and the certificates are held in the certificate library.

Two related articles cover how those documents are read. Mass spectrometry peptide testing explains how an observed mass is matched to an expected one and why charge states and adducts appear in the spectrum. How to verify a peptide certificate of analysis sets out which fields on a certificate carry weight, including lot identity, test dates and the identity of the testing laboratory. Purity and identity information on this page is limited to exactly that: third-party HPLC and mass spectrometry, with one certificate per lot. No purity figure, lot number or testing-laboratory name is stated here, because those values belong to individual lots and are reported on the certificate for the lot supplied.