What is SNAP-8?
SNAP-8, also cataloged as Acetyl Octapeptide-3 and Acetyl Glutamyl Heptapeptide-3, is a synthetic octapeptide bearing CAS number 868844-74-0. Its molecular formula is C41H70N16O16S with an average molecular weight of approximately 1075.2 g/mol, and its primary sequence is Ac-Glu-Glu-Met-Gln-Arg-Arg-Ala-Asp-NH2 (one-letter: Ac-EEMQRRAD-NH2). The molecule comprises eight amino acid residues and carries an N-terminal acetyl group and a C-terminal primary amide, both common synthetic modifications used to cap the peptide termini.
Structurally, SNAP-8 is a linear, non-cyclic peptide whose sequence corresponds to the N-terminal segment of SNAP-25, one of the core proteins of the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) complex. The chain is rich in charged and polar residues, including two N-terminal glutamic acid residues, two adjacent arginine residues, and a C-terminal aspartic acid, which together give the molecule high aqueous solubility and a net charge that is pH-dependent. A single methionine residue provides the only sulfur atom in the structure and is a site of potential oxidation, a consideration relevant to handling and storage. Terminal acetylation and amidation remove the free alpha-amino and alpha-carboxyl charges at the chain ends, altering the molecule's overall charge distribution relative to the unmodified peptide.
In the research literature, peptide fragments of this class are studied in laboratory models of SNARE-complex assembly and catecholamine exocytosis, where synthetic SNAP-25-derived sequences are used as in-vitro tools to probe protein-protein assembly at the biochemical level. American Peptides supplies SNAP-8 strictly as a research reagent for laboratory research use only. This monograph is provided for reference and characterization purposes; it makes no representation regarding the biological activity, efficacy, or outcome of the compound, and the material is not a drug, food, or cosmetic and is not intended for human or veterinary use.
Reconstitution & handling
For laboratory handling, SNAP-8 is typically dissolved in sterile water or a suitable aqueous buffer, consistent with the high water solubility conferred by its multiple charged glutamate, arginine, and aspartate residues. Bacteriostatic or sterile water is commonly selected as a reconstitution solvent in laboratory protocols; a small fraction of an organic co-solvent may be used where a stock solution requires it, though the peptide's polarity generally makes aqueous systems sufficient. Solvent should be added slowly against the vial wall and the vial allowed to stand so the lyophilized powder dissolves without vigorous agitation, which can promote foaming and mechanical stress on the peptide.
Because the sequence contains a methionine residue susceptible to oxidation, reconstituted solutions are best prepared fresh and handled with minimal exposure to air, light, and repeated warming. Where a working stock is not consumed immediately, aliquoting into single-use fractions and storing frozen limits degradation from repeated freeze-thaw cycles. All reconstitution steps described here are general laboratory-solubility guidance for in-vitro research handling only and do not constitute directions for administration to humans or animals.
Storage & stability
Lyophilized SNAP-8 is best stored at -20 C in a sealed, desiccated container protected from light, under which conditions the powder is stable for extended periods. After reconstitution, solutions should be kept refrigerated at 2-8 C for short-term use and frozen at -20 C or below for longer intervals, ideally in single-use aliquots to avoid repeated freeze-thaw cycles. The methionine residue in the sequence makes the molecule sensitive to oxidation, so limiting exposure to air, elevated temperature, and light helps preserve chromatographic purity over time.
How it's tested
Each lot of SNAP-8 is characterized by reversed-phase high-performance liquid chromatography (HPLC) to establish purity of ≥98%, and identity is confirmed by mass spectrometry (MS) against the theoretical molecular weight of approximately 1075.2 g/mol for the C41H70N16O16S composition. A certificate of analysis (COA) documenting the HPLC purity trace and MS identity confirmation is available for each batch. These analyses support characterization of the reference material for laboratory research use only and are not a determination of suitability for any human, veterinary, or cosmetic application.