What is ARA-290?
ARA-290, also referred to in the literature as cibinetide, is a synthetic linear undecapeptide (11 residues) classified among the erythropoietin-derived peptides. Its defined primary sequence is Pyr-Glu-Gln-Leu-Glu-Arg-Ala-Leu-Asn-Ser-Ser, in which the N-terminus is a pyroglutamate (Pyr) residue formed by intramolecular cyclization of an N-terminal glutamine. The molecule carries the empirical formula C55H82N18O18 and a molecular weight of 1259.34 g/mol, and it is registered under CAS number 1208243-50-8.
Structurally, the ARA-290 sequence corresponds to a segment of the helix-B surface of the erythropoietin molecule. It reproduces a surface region of the parent protein that is associated in the literature with the innate repair receptor complex rather than the classical erythropoietin receptor homodimer, which is why the peptide is frequently described as a non-erythropoietic, non-hematopoietic analog. As a short linear peptide it lacks the disulfide architecture and glycosylation of full-length erythropoietin, making it a discrete, chemically defined reference standard.
In the research setting, ARA-290 is used as a molecular tool in innate-repair-receptor and tissue-protection research, including in-vitro receptor-binding assays and neuro-inflammatory and small-fiber research models. This listing describes the peptide strictly as a characterized chemical reagent for laboratory research use only. It is not a drug, dietary supplement, or article intended for human or veterinary diagnostic or therapeutic use, and no physiological or clinical outcomes are represented.
Reconstitution & handling
ARA-290 is supplied as a lyophilized (freeze-dried) solid and requires reconstitution into a liquid vehicle before use in bench work. For a peptide of this composition, bacteriostatic or sterile water is the most common primary solvent; the diluent is directed slowly down the inner wall of the vial rather than injected forcefully onto the powder, and the vial is then left to stand and swirled gently to bring the material into solution. The arginine and glutamate residues confer reasonable aqueous handling behavior, so mechanical agitation such as vortexing or shaking is generally avoided to limit foaming, shear, and localized denaturation.
If dissolution is incomplete, chemistry-appropriate steps include brief additional standing time or, for peptides that are sparingly soluble at neutral pH, preparation of a small stock in a compatible co-solvent before dilution into the working aqueous buffer. All reconstitution should be performed under clean technique in an appropriate volume so that the resulting concentration is known and consistent for a given experimental protocol. Reconstituted solutions are handled as research reagents only; this section addresses solvent chemistry and physical handling and does not describe administration.
Storage & stability
In lyophilized form, ARA-290 is best stored desiccated and protected from light, typically at -20 C for long-term storage, where the dry peptide is comparatively stable over extended periods. The sealed vial should be equilibrated to room temperature before opening to minimize condensation on the cold solid. Once reconstituted, the peptide is far less stable and should be kept refrigerated at 2-8 C for short-term use or aliquoted and frozen at -20 C or below for longer intervals; single-use aliquots are preferred so that repeated freeze-thaw cycles, which promote aggregation and degradation of the peptide backbone, are avoided.
How it's tested
Identity and purity of ARA-290 are verified analytically prior to release. Reversed-phase high-performance liquid chromatography (HPLC) is used to quantify chromatographic purity, confirmed here at ≥99%, by resolving the main peptide peak from process-related and degradation impurities. Mass spectrometry (MS), typically electrospray-ionization or MALDI-TOF, confirms molecular identity by matching the observed mass to the theoretical average mass derived from the C55H82N18O18 formula and 1259.34 g/mol molecular weight. Each lot is accompanied by a Certificate of Analysis (COA) documenting the measured purity, mass confirmation, and appearance, providing traceable, verifiable characterization of the material.