Cartalax is a synthetic three-residue peptide with the sequence Ala-Glu-Asp (AED, CAS 85806-95-7, C12H19N3O8, 333.29 g/mol); it belongs to the Khavinson family of short peptides, is the direct three-residue relative of the tetrapeptide Epithalon (AEDG), and is supplied as a lyophilized powder for in vitro research into nucleic-acid interaction and gene-expression readouts in cultured cells. This guide covers what the compound is at the level of sequence and chemistry, how it fits with the other short peptides in the catalog, how a laboratory confirms its identity, and how a 20 mg vial converts to a working stock.
What is the Cartalax peptide?
Cartalax is a tripeptide: three amino acids joined by two peptide bonds. Written N-terminus to C-terminus the sequence is L-alanine, L-glutamic acid, L-aspartic acid, abbreviated AED or H-Ala-Glu-Asp-OH. PubChem lists the compound as alanyl-glutamyl-aspartic acid (CID 87815447) and records "T-31 peptide" as a further synonym. Two of the three residues (Glu and Asp) carry acidic side chains and the molecule also carries the free C-terminal carboxylate, so at neutral pH it is a small, highly polar, net-negative species. That is why it dissolves readily in water and why it is shipped as a lyophilized powder rather than a solution.
"Cartalax" is a catalog name from the Khavinson short-peptide series, not a chemical descriptor. In a research context the compound is defined by its sequence and identifiers, and that is how it should appear in a methods section and on a Certificate of Analysis. The naming history and the catalog-name convention are covered separately in Cartalax naming and the Khavinson short-peptide family.
Identifiers at a glance
| Property | Value |
|---|---|
| Catalog name | Cartalax |
| Sequence | Ala-Glu-Asp (AED); H-Ala-Glu-Asp-OH |
| Chemical name | L-Alanyl-L-glutamyl-L-aspartic acid |
| CAS number | 85806-95-7 |
| PubChem CID | 87815447 |
| Molecular formula | C12H19N3O8 |
| Molecular weight | 333.29 g/mol (free peptide) |
| Expected [M+H]+ | about 334.1 |
| Form supplied | Lyophilized powder, 20 mg vial |
The molecular weight above is for the free peptide. If a lot is supplied as a salt (for example an acetate), the COA will say so and the effective mass per mole will be slightly higher; use the value printed on the lot COA for concentration calculations.
How does Cartalax relate to the other Khavinson short peptides?
Khavinson short peptides are a family of synthetic di-, tri- and tetrapeptides built from a small set of charged and polar residues, chiefly glutamate, aspartate, lysine, arginine, glycine and alanine. They are studied in vitro as short-peptide bioregulator research compounds, where the laboratory question is how a very short, highly charged peptide interacts with nucleic acids and whether that interaction shows up in gene-expression assays. The catalog now carries five members of the family.
| Catalog name | Sequence | Length | CAS number | Formula | MW (g/mol) |
|---|---|---|---|---|---|
| Cartalax | Ala-Glu-Asp (AED) | 3 | 85806-95-7 | C12H19N3O8 | 333.29 |
| Epithalon | Ala-Glu-Asp-Gly (AEDG) | 4 | 307297-39-8 | C14H22N4O9 | 390.35 |
| Testagen | Lys-Glu-Asp-Gly (KEDG) | 4 | 1026993-38-3 | C17H29N5O9 | 447.44 |
| Livagen | Lys-Glu-Asp-Ala (KEDA) | 4 | 433257-50-2 | C18H31N5O9 | 461.47 |
| Pinealon | Glu-Asp-Arg (EDR) | 3 | 175175-23-2 | C15H26N6O8 | 418.41 |
The Glu-Asp pair runs through every entry. Cartalax is Epithalon with the C-terminal glycine removed: the sequences are AED and AEDG, and the difference is exactly one glycine residue, 57.06 g/mol (390.35 minus 333.29). Cartalax and Pinealon are both tripeptides but overlap only in the Glu-Asp core, with alanine at the N-terminus in one and arginine at the C-terminus in the other. The tetrapeptides Testagen and Livagen swap the N-terminal alanine of Epithalon for lysine and then differ from each other at the final residue. Keeping these single-residue relationships straight is the whole task when confirming which compound is in a vial.
How is Cartalax studied in vitro?
The work is mechanistic and cell-based. A typical design exposes cultured cells to the peptide at defined molar concentrations and reads out messenger-RNA levels by quantitative PCR, reporter-gene activity, or chromatin-accessibility measurements, always against vehicle controls and ideally a scrambled-sequence peptide of the same length and charge. The methods are laid out in gene-expression assays in vitro. Because Cartalax and Epithalon differ by a single glycine, running the two side by side at matched molarity is the natural way to ask whether the C-terminal residue changes a readout. The cell line is a design choice: connective-tissue-derived lines such as primary chondrocytes or fibroblasts are common models for this compound in the literature, but the readouts are the same molecular measurements used for any short peptide.
How do you confirm you have Cartalax and not Epithalon?
Three checks on the Certificate of Analysis settle it:
- Mass spectrometry. The observed [M+H]+ for Cartalax should be about 334.1. Epithalon gives about 391.1, Pinealon about 419.2, Testagen about 448.2 and Livagen about 462.2. A 57-unit gap between Cartalax and Epithalon is unambiguous on any instrument. The approach is described in mass spectrometry for peptide identity confirmation.
- HPLC purity. A single dominant peak reported as a percentage of total area; the catalog specification is approximately 99%.
- Identifiers. The CAS number, sequence and formula printed on the COA should match the table above and the product page. The line-by-line COA guide shows where each item appears.
Stock concentration math for a 20 mg vial
Cartalax is listed as a 20 mg vial. Reconstituting the full vial in 1 mL of reconstitution solution gives 20 mg/mL, which at 333.29 g/mol is a 60.0 mM stock; 2 mL gives 10 mg/mL (30.0 mM) and 4 mL gives 5 mg/mL (15.0 mM). Working solutions in the micromolar range are then prepared by serial dilution in assay medium. Because the molecule is small, a given mass of Cartalax contains more moles than the same mass of a tetrapeptide: 20 mg of Cartalax is 60.0 micromol, whereas 20 mg of Testagen is 44.7 micromol. Always compare short peptides by molarity, not by mass. The arithmetic follows the reconstitution math guide.
| Solvent added | Concentration (mg/mL) | Molarity (mM) |
|---|---|---|
| 1 mL | 20 | 60.0 |
| 2 mL | 10 | 30.0 |
| 4 mL | 5 | 15.0 |
Related research guides
- Cartalax naming and the Khavinson short-peptide family
- Epithalon: a tetrapeptide bioregulator
- Khavinson short peptides: Testagen (KEDG) and Livagen (KEDA)
- Pinealon: a tripeptide bioregulator
- Short-peptide bioregulator research compounds: an overview
Research-use note
All materials discussed are supplied for in vitro laboratory research use only, and are not for human or animal use.
