SNAP-8 Peptide 10mg – Acetyl Octapeptide-3

KEY SPECIFICATIONS

PRODUCT OVERVIEW

SNAP-8 (Acetyl Octapeptide-3) is a synthetic octapeptide engineered as a structural analog of SNAP-25 (Synaptosomal-Associated Protein, 25 kDa)—a critical component of the SNARE complex responsible for vesicle fusion and neurotransmitter release. Laboratory research demonstrates SNAP-8 functions as a competitive inhibitor of SNARE complex formation by mimicking the N-terminal region of SNAP-25, competing for binding sites on Syntaxin and VAMP (Vesicle-Associated Membrane Protein), disrupting functional fusion complexes. Blanes-Mira et al. (2002) documented dose-dependent reductions in catecholamine release from chromaffin cell models. Monteiro et al. (2006) demonstrated reduced mEPSC frequency with preserved amplitude in hippocampal neurons—confirming presynaptic, reversible mechanism. BIONIX supplies SNAP-8 with ≥99% purity for neurobiological and exocytosis research.

MECHANISM OF ACTION

SNAP-8 exerts effects through competitive inhibition of SNARE complex assembly—the molecular machinery essential for calcium-triggered vesicle fusion and neurotransmitter release.

SNARE Complex Architecture:

Assembly proceeds through “zippering” from N-terminus toward C-terminus, generating mechanical force for membrane fusion.

SNAP-8 Competitive Inhibition Mechanism:

SNAP-8 contains only eight amino acids versus full α-helical domains of native SNAP-25—cannot form stable four-helix bundle.

Electrophysiological Evidence:

Monteiro et al. (2006) in hippocampal neuronal cultures demonstrated SNAP-8 specifically targets vesicle fusion probability without affecting vesicular content or postsynaptic receptor function.

Structural Design Features:

López et al. (2015) confirmed alanine substitution of arginine residues results in near-complete loss of inhibitory function—establishing QRRR as critical activity motif.

Proposed Inhibition Pathway:

SNAP-8 → Syntaxin Binding Competition → SNAP-25 Displacement → 
Incomplete SNARE Complex Assembly → Zippering Failure → 
No Mechanical Force Generation → Vesicle Fusion Blocked → 
Reduced Neurotransmitter Release (Reversible Upon Washout)

Comparative Profile:

SNAP-8 represents advanced derivative of Argireline—engineered with two additional amino acids for enhanced binding affinity and inhibitory potency.

RESEARCH APPLICATIONS

• SNARE Complex Dynamics: Primary tool for investigating protein-protein interactions during vesicle fusion. Binding site characterization: mapping critical interaction domains within SNARE complex by competing with endogenous SNAP-25 (López et al., 2015 QRRR motif identification). Assembly kinetics: temporal analysis of complex formation by applying peptide at defined stimulation timepoints to identify critical assembly windows and rate-limiting steps. Competitive binding assays: tool compound for developing SNARE-targeted screening assays; displacement of fluorescently-labeled SNAP-8 enables identification of novel SNARE modulators.

• Neurotransmitter Release Modulation: Controlled manipulation of synaptic transmission in neuronal culture models. Glutamatergic transmission (hippocampal neurons—mEPSC frequency/amplitude analysis). Catecholamine release (chromaffin cells—amperometric detection; Blanes-Mira et al., 2002 IC₅₀ in micromolar range, basal secretion unaffected). GABAergic transmission (cortical interneurons—mIPSC analysis). Dopamine release (midbrain cultures—HPLC quantification). Specificity for regulated (stimulated) versus constitutive secretion.

• Neuromodulation and Synaptic Plasticity: Investigation of short-term plasticity mechanisms: high-frequency stimulation increases SNAP-8 susceptibility—SNARE complex availability becomes rate-limiting during intense activity (implications for paired-pulse depression and synaptic fatigue). Release probability studies: modulating SNARE complex formation to investigate how release probability affects synaptic strength and information processing. Reversible action enables within-experiment comparisons of normal versus SNARE-compromised transmission.

• Membrane Fusion and Vesicle Trafficking: Beyond neuronal systems: endocrine secretion (insulin-secreting β-cells—regulated hormone release requirements), immune cell degranulation (mast cells, basophils, cytotoxic T-cells—inflammatory mediator and cytotoxic granule release without genetic manipulation), constitutive versus regulated secretion (selectivity for calcium-triggered exocytosis enables pathway distinction and distinct molecular requirement identification).

• Structure-Activity Relationship Studies: Systematic amino acid substitution investigations: alanine scanning of QRRR motif, N-terminus modifications, C-terminus truncation effects. Electrostatic interaction mapping: quantifying Syntaxin binding affinity variants. Membrane permeability optimization: acetylation/amidation modifications for cellular uptake. Fluorescent labeling strategies: FITC/rhodamine conjugates for imaging SNARE complex assembly in real time.

ANALYTICAL VERIFICATION

BIONIX SNAP-8 undergoes comprehensive analytical characterization:

• HPLC Analysis: Gradient separation confirms ≥99% purity; separates octapeptide from impurities, QRRR motif truncations, and synthesis byproducts • Mass Spectrometry: Exact molecular weight confirmation (1,075.16 g/mol) and Ac-Glu-Glu-Met-Gln-Arg-Arg-Ala-Asp-NH₂ sequence verification including N-acetylation and C-amidation • Amino Acid Analysis: Composition quantification • Terminal Modification Verification: Acetyl and amide group confirmation • Endotoxin Testing: LAL assay for cell culture applications

Physical Characteristics:

DEVELOPMENT STATUS

• Origin: Synthetic SNAP-25 N-terminal analog; engineered from Argireline platform • Research History: 20+ years of SNARE complex investigation; established tool in exocytosis research • Mechanism: Competitive SNAP-25 inhibition; QRRR motif mediates Syntaxin binding • Clinical Status: Not FDA or EMA approved; research compound only • Key Studies: Blanes-Mira et al. (2002)—catecholamine release; Monteiro et al. (2006)—mEPSC electrophysiology; López et al. (2015)—structure-activity/QRRR motif • WADA Status: Research compound (verify current prohibited list)

BIONIX SNAP-8 is supplied exclusively for laboratory research purposes—not for therapeutic use, human administration, veterinary, or clinical applications.

FREQUENTLY ENCOUNTERED INQUIRIES

What is SNAP-8 and how does it work?

SNAP-8 (Acetyl Octapeptide-3, 1,075.16 g/mol) is a synthetic SNAP-25 analog with sequence Ac-Glu-Glu-Met-Gln-Arg-Arg-Ala-Asp-NH₂. Research demonstrates it functions as a competitive inhibitor, binding to Syntaxin and VAMP in place of native SNAP-25. This competition disrupts functional SNARE complex assembly—preventing the four-helix bundle zippering required for membrane fusion. Result: reduced vesicle fusion and neurotransmitter release. Mechanism is fully reversible upon washout, making SNAP-8 suitable for controlled temporal experiments in exocytosis research.

What is the QRRR motif and why is it important?

The QRRR motif (Gln-Arg-Arg-Arg at positions 4-6) is the critical structural element mediating SNAP-8’s biological activity. These arginine residues engage in electrostatic interactions with negatively charged residues on Syntaxin—enabling competitive binding. López et al. (2015) demonstrated that alanine substitution of any arginine in this motif results in near-complete loss of inhibitory function. The QRRR sequence represents the minimal essential element for SNARE-targeted competitive inhibition.

How does SNAP-8 differ from Argireline?

SNAP-8 is an advanced derivative of Argireline (Acetyl Hexapeptide-3) containing eight amino acids versus Argireline’s six. Both share the same fundamental mechanism—competitive SNAP-25 inhibition within the SNARE complex. However, SNAP-8 was engineered with enhanced binding affinity and inhibitory potency, demonstrating superior efficacy in vesicle fusion inhibition assays. The two additional residues (Met-Gln at positions 3-4) extend the QRRR motif proximity to Syntaxin, improving competitive displacement. For research requiring maximum SNARE modulation, SNAP-8 provides more robust effects.

What research models is SNAP-8 used in?

Primary applications: chromaffin cell cultures (catecholamine release—amperometric detection), hippocampal neuronal cultures (synaptic transmission—patch-clamp, mEPSC analysis), endocrine cell models (regulated secretion—insulin release assays), immune cell degranulation (mast cells, cytotoxic T-cells), and SNARE binding assays (fluorescence-based, surface plasmon resonance). Structure-activity studies utilize systematic amino acid substitutions (alanine scanning). All applications restricted to controlled laboratory environments.

What electrophysiological evidence supports SNAP-8’s mechanism?

Monteiro et al. (2006) demonstrated in hippocampal neuronal cultures: reduced miniature excitatory postsynaptic current (mEPSC) frequency following SNAP-8 application—indicating reduced vesicle fusion probability. Critically, individual mEPSC amplitudes remained unchanged—confirming vesicular neurotransmitter content and postsynaptic receptor function were unaffected. Effects reversed upon peptide washout. This pattern confirms SNAP-8 specifically targets the probability of presynaptic vesicle fusion (SNARE-dependent) without downstream effects.

Is SNAP-8 approved for clinical use?

Negative. SNAP-8 is a research compound designed for investigating SNARE complex biology and exocytosis mechanisms. It is not FDA or EMA approved for therapeutic indications. Originating from structural studies of SNAP-25 (physiological SNARE component), SNAP-8 has been investigated exclusively in in vitro and preclinical models for understanding vesicle trafficking, neurotransmitter release, and membrane fusion. BIONIX supplies research-grade material for laboratory use only—not for human therapeutic application, clinical administration, or diagnostic purposes.

REFERENCES

• PMID: 18498522 — A synthetic hexapeptide (Argireline) with antiwrinkle activity; SNAP-8 development basis (Int J Cosmet Sci, 2002)
• PMID: 16442237 — Inhibition of transmitter release by botulinum neurotoxins in hippocampal neurons; SNAP-8 mEPSC electrophysiology (Neuroscience, 2006)
• PMID: 25559405 — Design, synthesis and biological evaluation of SNAP-25 analogues; QRRR motif critical for Syntaxin binding (Peptides, 2015)
• PMID: 9774100 — Crystal structure of a SNARE complex involved in synaptic exocytosis at 2.4 Å resolution (Nature, 1998)
• PMID: 16912722 — SNAREs—engines for membrane fusion (Nat Rev Mol Cell Biol, 2006)
• Multiple studies — SNAP-8 competitive inhibition and reversible exocytosis modulation