Dermaseptin-S4 , CAS No.151896-15-0

CAS: 151896-15-0 Cat. No.: D1419803 Fórmula: C₁₃₂H₂₂₉N₃₅O₃₂S Peso molecular: 2850.51

Storage

Store at -20°C

Shipped In

Ice chest + Ice pads

Descripción general

Dermaseptin-S4 is an antimicrobial peptide derived from frog skin against filamentous fungi.

Specifications

Condiciones de almacenamiento de almacenamiento

Store at -20°C

Enviado en

Ice chest + Ice pads

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Tipo de acción

INHIBITOR

Nombres e identificadores

• Peso molecular: 2850.51

Application Protocols

General research protocols (literature/practice; adjust to your system). Not item-specific and not a performance claim.

• MIC determination (broth microdilution)

  • Prepare a sterile 1–5 mM stock in water or suitable buffer. Perform twofold serial dilutions in cation-adjusted Mueller–Hinton (bacteria) or RPMI 1640 with MOPS (fungi). Inoculate to 5×10^5 CFU/mL, incubate 16–20 h at 35 ± 2 °C. Read MIC as lowest concentration with no visible growth. Include sterility and solvent controls.

• Liposome dye-leakage assay

  • Encapsulate self-quenching calcein or ANTS/DPX in LUVs (e.g., POPC/POPG). Equilibrate vesicles in assay buffer. Add peptide at defined P:L ratios (e.g., 1:50–1:200). Monitor fluorescence over time; normalize to 100% release with detergent (Triton X-100). Control ionic strength to modulate electrostatics.

• Circular dichroism (secondary structure)

  • Buffer: 10 mM phosphate or 10–20 mM acetate; use low-absorbing buffers. Record 190–260 nm spectra at 20–25 °C. For helix induction, titrate TFE (0–30%) or add SDS micelles/SMALPs. Report mean residue ellipticity.

• SPR binding to LPS or lipid vesicles

  • Immobilize ligand or peptide per instrument chemistry. Run multi-cycle kinetics with appropriate blanks and mass transport checks. Use low-salt buffers to enhance signal; regenerate surfaces mildly to preserve activity.

• Cytoplasmic membrane depolarization (bacteria)

  • Stain cells with DiSC3(5); add peptide across a concentration range; monitor fluorescence increase indicative of depolarization. Maintain temperature and medium conditions consistently across replicates.

Note: Optimize concentrations, buffers, and incubation times empirically. Implement appropriate biosafety and waste procedures.

Biological Roles

General/literature context (not item-specific claims)

• Origin and function: Dermaseptins constitute a family of cationic amphipathic peptides isolated from Phyllomedusa (leaf frog) skin secretions, a component of innate chemical defense. They display broad-spectrum antimicrobial activity in vitro across bacteria, fungi, and protozoa, attributed primarily to interactions with anionic biomembranes.
• Mechanistic themes: Electrostatic attraction to negatively charged membranes, surface accumulation, insertion as an α-helix, and membrane permeabilization/disruption. Some studies suggest secondary intracellular targets at sub-lytic concentrations (e.g., nucleic acid binding), but membrane effects dominate at typical assay conditions.
• Biophysical signatures: Increased helicity in membrane-mimetic environments, blue-shift of intrinsic Trp fluorescence upon membrane binding (where applicable), and concentration-dependent dye leakage from lipid vesicles enriched in PG/CL.
• Selectivity concept: Preferential activity toward prokaryotic/negatively charged membranes versus zwitterionic eukaryotic membranes is a common AMP paradigm; ionic strength, serum proteins, and lipid composition modulate this selectivity in model systems.
• Stability and metabolism: Susceptible to proteolysis by extracellular and intracellular proteases. N-/C-terminal modifications (e.g., amidation), D-residue incorporation, or cyclization are strategies explored in literature to enhance stability without compromising activity in models.

Note

• The above summarizes biological roles described in the AMP literature and does not imply performance of this specific item in any biological system. For research use only.

Buffer Applications

Applicability

• While Dermaseptin-S4 is not a classical buffering agent, buffer selection is central to its dissolution, structural state, and activity in model systems.

Practical buffer guidance (literature/practice)

• Reconstitution buffers: Start with nuclease-/protease-free water or low-ionic-strength acetate (10–50 mM, pH 5.0–5.5) to ensure cationic charge and efficient dissolution. For highly hydrophobic variants, pre-dissolve in minimal DMSO/HFIP and dilute into buffer.
• Experimental buffers: Use HEPES or phosphate (10–20 mM, pH 7.0–7.4) for biophysical assays (CD, ITC, SPR). For membrane leakage assays, maintain ionic strength ≤100–150 mM NaCl to preserve electrostatic interactions unless your model requires physiological salt.
• Stability considerations: Avoid strong base and extended exposure at elevated temperatures. If metal-catalyzed oxidation of sensitive residues (e.g., Met, Trp) is a concern, include metal chelators (e.g., 0.1–1 mM EDTA) where compatible.
• Filtration: Sterile-filter reconstituted solutions (0.22 µm PES) when used in microbiology workflows to remove particulates while minimizing peptide loss; pre-rinse filter devices to reduce adsorption.
• Adsorption mitigation: Use low-bind plasticware or silanized glass; add 0.05–0.1% carrier protein (e.g., BSA) only if it does not interfere with the assay, recognizing this can sequester cationic peptides.

Non-applicable

• Recipes for classical buffer systems (Good’s buffers) are standard and outside the scope of this peptide listing; consult biochemistry references for detailed formulations.

Green Alternatives

Context

• Dermaseptin-S4 is itself a peptide reagent rather than an organic solvent or bulk chemical. “Green” considerations focus on solvent and buffer choices for reconstitution and assays.

Lower-impact choices (general guidance)

• Prefer water-based systems: Use ultrapure water and simple aqueous buffers (acetate, phosphate, HEPES) instead of fluorinated alcohols or high DMSO content whenever feasible.
• Minimize organic cosolvents: If needed for initial dissolution, use the smallest possible volume of ethanol or DMSO, then dilute promptly into aqueous media. Avoid HFIP unless essential for secondary-structure work.
• Detergent selection: Choose biodegradable or low-toxicity surfactants (e.g., small amounts of polysorbates) only when necessary; validate that they do not alter peptide function.
• Energy efficiency: Store lyophilized material at −20 °C as recommended; for solutions, consider +4 °C short-term to reduce freeze energy load, provided stability is established.

Comparison table (literature/practice; not item-specific)

• Aqueous acetate buffer (pH 5–5.5): Good solubility/charge; low environmental impact; limited buffering at neutral pH.
• Phosphate buffer (pH 7–7.4): Widely available; minimal hazard; may reduce electrostatic interactions vs low-ionic conditions.
• DMSO: Excellent solvency; higher environmental/biological impact; keep ≤1–2% in assays.
• HFIP/TFE: Powerful helix inducers; volatile and hazardous; reserve for structural studies only and capture vapors with proper engineering controls.

Pharmaceutical Uses

Scope

• Dermaseptin-S4 is supplied for research use only. No medical, diagnostic, or therapeutic applications are claimed or supported for this product.

Research/formulation context (general literature)

• Preformulation studies: Cationic amphipathic peptides like dermaseptins are evaluated as model compounds for peptide formulation challenges—solubility enhancement, aggregation control, and stabilization (lyophilization cycles, bulking agents, counterion exchange).
• Delivery research: Used as a research tool to investigate membrane interaction and cell-penetration phenomena, informing design of peptide-based delivery vehicles. Studies may explore conjugation to cargos (fluorophores, biotin) for tracking or pull-down assays.
• Reference materials: Serve as positive controls in antimicrobial and membrane-modulation screening platforms to benchmark performance of novel AMP analogs.
• Analytical method development: Useful for validating MS (MALDI/ESI) settings, HPLC gradients, and capillary electrophoresis methods tailored to cationic helical peptides.

Regulatory note

• Not an approved active pharmaceutical ingredient (API) or excipient per pharmacopeial monographs. Any translational or preclinical development must source GMP-grade material and follow applicable regulatory guidance; this catalog item is intended strictly for non-clinical laboratory research.

Physical Properties

Item-specific facts (from Product Data)

• Appearance: Not specified for this item; refer to CoA/Spec Sheet.
• Molecular weight: Not specified for this item; refer to CoA/Spec Sheet.

General/literature values for dermaseptin peptides (not item-specific)

• Physical state: Commonly supplied lyophilized as a white to off-white solid; becomes clear to slightly opalescent when dissolved in water or dilute acid.
• Solubility (literature guidance): Water-soluble as a cationic peptide; improved solubility in mildly acidic aqueous media (e.g., 0.1% TFA, 10–50 mM HCl, or acetate buffer). If highly hydrophobic variants are used, initial dissolution in small volumes of DMSO or HFIP followed by aqueous dilution is common.
• pI/charge: Dermaseptins typically have net positive charge at neutral pH (due to multiple Lys), facilitating binding to anionic membranes.
• Conformation: Predominantly random coil in pure water; adopts α-helix in membrane-mimetic media (SDS micelles, TFE/water, lipid vesicles) per CD and NMR literature.
• Stability: Peptides are generally stable as lyophilized powders at −20 °C, protected from moisture and light. In solution, stability depends on sequence, pH, temperature, and presence of proteases.

Not provided for this item (consult CoA/SDS)

• Exact extinction coefficient, ε(280)
• Refractive index, density, melting point/boiling point, logP, pKa values All such parameters are Not specified for this item; refer to CoA/Spec Sheet.

Quality and Grades

Item-specific facts (from Product Data)

• Grade/purity: Not specified for this item; refer to CoA/Spec Sheet.

How to interpret peptide quality (general guidance)

• Purity reporting: Peptide products are commonly reported by analytical HPLC purity (area %) and are characterized by MS (ESI or MALDI) and, when needed, amino acid analysis or sequencing. Typical research grades include:
  • Crude: minimal purification; for screening or further synthesis.
  • Desalted: salts removed; still heterogeneous.

  • 70–80% HPLC: suitable for preliminary biological screening.

  • 90–95% HPLC: standard for most biochemical experiments.

  • 98% HPLC: for sensitive biophysical/structural studies.

• Modifications: Terminal amidation (C-terminal –CONH2) is frequent for dermaseptins, stabilizing charge and bioactivity in models. Presence/absence must be confirmed on the CoA.
• Counterions: TFA, acetate, or chloride counterions affect mass and solubility. CoA should indicate counterion content.
• Moisture and residual solvents: Lyophilized peptides can absorb water; CoA may list residual solvent and water by KF. For quantitative work, gently dry under vacuum if appropriate.

Recommendations

• Verify the CoA for: sequence, exact average/monoisotopic mass, terminal modifications, counterion, HPLC chromatogram, and MS. Match these to your method requirements (MIC assays, CD/NMR, membrane studies).
• If low-UV background is critical (e.g., CD at 190–220 nm), request high-purity and minimal TFA content or exchange counterion.

Reaction and Applications

Item-specific facts (from Product Data)

• Manufacturer applications: Not provided in Product Data.

Research applications (literature/practice; not item-specific claims)

• Antimicrobial peptide (AMP) model: Dermaseptin peptides are widely used to study membrane-active mechanisms, including binding to anionic phospholipids, helix–membrane alignment, and pore formation. Employed in dye-leakage assays with LUVs/GUVs, membrane depolarization in bacteria, and lipid phase modulation studies.
• Biophysical characterization: CD to quantify α-helix content in TFE or membrane mimetics; NMR/MD simulations to probe helix topology; SPR/ITC to measure lipid or LPS binding; fluorescence spectroscopy leveraging intrinsic Trp (if present in the sequence) to monitor environment polarity.
• Microbiology workflows: Determination of MIC/MBC against bacteria/fungi in broth microdilution; time-kill kinetics; synergy testing with conventional antibiotics; biofilm disruption models.
• Surface interactions: Studies of peptide adsorption to materials and supported lipid bilayers by QCM-D, AFM, and neutron/X-ray reflectivity.
• Structure–activity relationships: Alanine scanning, truncations, and terminal modifications to tune helicity, amphipathicity, and proteolytic stability.

Practical tips

• Prepare fresh stocks in sterile, low-salt buffer. Filter (0.22 µm) if compatible. Avoid repeated freeze–thaw by small aliquoting.
• For lipid assays, confirm peptide:lipid ratios (e.g., P:L 1:50–1:200) and equilibrate at target temperature.
• Control experiments: Include scrambled or charge-reversed sequences and peptide-free blanks to deconvolute membrane vs non-membrane effects.

Reaction Conditions

Not a classical small-molecule reagent; however, common chemistries used with cationic peptides like Dermaseptin-S4 are summarized below (literature/practice; not item-specific):

• NHS-ester labeling (amines)

  • Solvent/buffer: 50–100 mM sodium bicarbonate or HEPES, pH 8.0–8.5 (amine deprotonation enhances reactivity). Avoid Tris/glycine which compete.
  • Temperature/time: RT, 30–120 min; protect from light if dye-labeled.
  • Stoichiometry: 1.1–5 equiv NHS-ester per reactive amine depending on desired DOF.
  • Quench: Add Tris or ethanolamine; purify by RP-HPLC or desalting.

• Maleimide–thiol coupling (requires Cys-containing analog)

  • Buffer: pH 6.5–7.0 in phosphate/HEPES with 1–5 mM EDTA.
  • Conditions: RT, 30–60 min; exclude oxidants; degas if needed.

• CuAAC (azide–alkyne “click”) on modified analogs

  • Solvent: Aqueous buffer with 5–20% tert-butanol or DMSO.
  • Catalyst: CuSO4 + sodium ascorbate; TBTA ligand to stabilize Cu(I).
  • Temperature/time: RT, 0.5–2 h; remove copper post-reaction.

• Surface immobilization (SPR/QCM-D)

  • EDC/NHS activation on carboxymethyl dextran chips; amine coupling at pH 4.5–5.5 to maximize surface amine protonation and minimize peptide self-neutralization.

Expected outcomes

• Yields and degrees of labeling vary with sequence and reaction stoichiometry. Verify by MS and chromatographic purity. Optimize empirically for each preparation.

Safety and Handling

Item-specific facts (from Product Data)

• GHS classification, signal word, pictograms, H-statements: Not specified for this item; refer to SDS.
• Storage conditions: Store at −20 °C.
• Shipped in: Ice chest + ice pads.
• Research use: For research use only.

General safety guidance for research peptides (literature/practice; defer to SDS)

• Hazards: Peptides of this class are not typically volatile but may cause irritation to skin, eyes, and respiratory tract as dust/aerosol. Avoid inhalation and contact.
• PPE: Wear lab coat, nitrile gloves, and safety glasses. Use a certified chemical fume hood or biosafety cabinet when weighing/reconstituting to minimize aerosolization.
• Handling: Allow container to equilibrate to room temperature in a desiccator before opening to prevent moisture uptake. Work with low-dust technique; wipe surfaces after handling.
• Incompatibilities: Avoid strong oxidizers and proteases. For solutions, avoid microbial contamination; use sterile technique and filtered solvents/buffers.
• First aid (overview; consult SDS): If inhaled—move to fresh air; seek medical attention if symptoms occur. Skin contact—wash with soap and water. Eye contact—rinse cautiously with water for several minutes. Ingestion—not expected route; rinse mouth, seek medical advice.
• Spill response: Gently dampen powder to avoid dust, absorb with inert material, and clean area. Dispose per institutional guidelines.
• Waste: Collect peptide-containing solutions and solids in appropriate containers; follow local regulations and institutional procedures.

Solvent Selection

Item-specific facts (from Product Data)

• No solvent specifications provided; refer to CoA/Spec Sheet for any vendor recommendations.

General guidance for cationic amphipathic peptides (literature/practice)

• Primary solvent: Water or aqueous buffers (e.g., 10–50 mM acetate, phosphate, or HEPES) are preferred. Mild acidity (e.g., 0.1% TFA or 10–20 mM HCl) can assist initial dissolution by protonating basic residues.
• Cosolvents: For highly hydrophobic sequences, pre-wet with a minimal volume of DMSO, ethanol, or HFIP, then dilute into buffer while vortexing. Keep final DMSO ≤1–2% for cell/microbe assays.
• Detergent/micelle aids: Small amounts of zwitterionic detergents (e.g., 0.05–0.1% CHAPS) or 10–30% TFE can promote α-helicity for spectroscopic studies; validate compatibility with your assay.
• Ionic strength: Low-ionic-strength buffers enhance electrostatic interactions with membranes; higher salt may reduce activity in model systems—tune to your objective.
• pH window: Maintain pH 5.0–7.4 to keep lysine residues protonated and preserve cationic character; avoid strong base that can induce deamidation or reduce stability over time.

Comparison (literature-based)

• Water vs DMSO: Water avoids solvent effects and is ideal for biological assays; DMSO helps dissolve hydrophobic sequences but can perturb membranes and microbes at >1%.
• Acetate vs phosphate: Acetate at pH ~5.0–5.5 favors cationic charge and solubility; phosphate is better buffered at neutral pH for binding/biophysics. Choose per assay demands.

Storage and Reconstitution

Item-specific facts (from Product Data)

• Storage conditions: Store at −20 °C.
• Shipping: Ice chest + ice pads.

General best practices (peptide handling; not item-specific specs)

• Upon receipt: Inspect vial integrity. If supplied lyophilized, allow to warm to room temperature in a desiccator before opening to avoid condensation.
• Long-term storage: Keep lyophilized material tightly capped, desiccated, and protected from light at −20 °C. For very long-term storage, −80 °C may be used if compatible with packaging.
• Reconstitution
  • Solvent: Use sterile, nuclease-/protease-free water or low-ionic-strength buffer. For hydrophobic sequences, pre-wet with minimal DMSO or HFIP before aqueous dilution.
  • Concentration: Prepare concentrated stock (e.g., 1–5 mM) if solubility permits. Mix gently; avoid vigorous foaming.
  • Filtration: If needed, 0.22 µm sterile filtration; pre-rinse filter to minimize adsorption.
• Aliquoting: Dispense single-use aliquots in low-bind tubes to avoid repeated freeze–thaw. Label with concentration, buffer, and date.
• Solution storage: Short term (hours–days) at 2–8 °C; longer storage at −20 °C or −80 °C depending on stability. Avoid multiple freeze–thaw cycles; thaw on ice.
• Stability factors: pH extremes, elevated temperature, light, and oxidants can degrade peptides. Consider inert atmosphere for oxidation-sensitive sequences (e.g., Met, Trp). If adsorption losses are significant, add compatible carrier (e.g., 0.05–0.1% BSA) while recognizing potential assay interference.

Note

• Exact solubility, sequence, and modifications are Not specified for this item; refer to the CoA/Spec Sheet and SDS for definitive instructions.

Structure and Identity

Item-specific facts (from Product Data)

• Product name: Dermaseptin-S4 (SKU: D1419803)
• CAS: 151896-15-0
• Molecular formula: Not specified for this item; refer to CoA/Spec Sheet.
• Molecular weight: Not specified for this item; refer to CoA/Spec Sheet.
• InChIKey: Not specified for this item; refer to CoA/Spec Sheet.
• SMILES: Not specified for this item; refer to CoA/Spec Sheet.

General/literature description (peptide family; not item-specific specs)

• Compound type: Cationic, amphipathic antimicrobial peptide (AMP) of the dermaseptin family, originally isolated from Phyllomedusa frog skin secretions.
• Structural features: Linear L-peptide, typically 27–34 amino acids; enriched in Lys and hydrophobic residues. Tends to adopt an α-helical conformation in membrane-mimetic environments (e.g., micelles, lipid bilayers), with clear amphipathic segregation of polar/cationic and hydrophobic faces.
• Functional groups: Multiple primary amines (Lys side chains and N-terminus) and a C-terminal carboxyl group (amidation status varies by preparation; check CoA). These confer cationic charge at physiological to mildly acidic pH.
• 2D description in words: A single polypeptide chain with alternating hydrophobic (Ala/Leu/Trp/Met) and cationic (Lys) residues arranged to support an amphipathic helix capable of membrane interaction and disruption.

Notes

• Exact amino acid sequence, terminal modifications (e.g., C-terminal amide), and average mass can differ by vendor and lot. For definitive identity attributes (sequence, exact MW, purity, modification state), consult the item’s CoA/Spec Sheet.

Synthetic Utility

Applicability

• As a biologically active peptide, Dermaseptin-S4 is not a general-purpose synthetic reagent. However, it has utility in chemical biology and bioconjugation workflows.

Utility in synthesis/chemical biology (general guidance)

• Conjugation handle: Primary amines (N-terminus and Lys ε-amines) support labeling with NHS esters (fluorophores, biotin), isothiocyanates, and aldehyde tags via reductive amination after periodate oxidation of appended glycans (if present). Site-specificity can be improved by orthogonal protecting strategies or by using sequence-engineered variants.
• Click chemistry: Incorporation of azido- or alkyne-bearing amino acids (e.g., AzF, Pra/PrK) in analogs enables CuAAC or SPAAC to surfaces, lipids, or probes for imaging and mechanistic studies.
• Crosslinking: Heterobifunctional linkers (e.g., SMCC, Sulfo-SMCC) can tether Dermaseptin analogs to nanoparticles, polymers, or proteins to study multivalency and membrane targeting.
• Solid-phase studies: Immobilization on sensor chips (e.g., CM5 via amine coupling) allows kinetic evaluation of lipid vesicle, LPS, or biomacromolecule interactions by SPR/QCM-D.
• Sequence–property mapping: Systematic residue substitutions (Ala-scan, charge swaps) support SAR objectives; chemical synthesis facilitates incorporation of D-residues or terminal capping to probe stability and helicity.

Caveats

• Conjugation can alter charge density, amphipathicity, and helicity, thereby modulating membrane interaction. Always characterize post-conjugation by MS and, if relevant, CD/fluorescence, and re-optimize assay conditions.

Target Specificity

Not applicable to this product type.

• This listing is a peptide reagent, not an antibody or target-directed affinity reagent. No antigen, clone, isotype, or species reactivity applies.
• For biochemical interaction preferences (e.g., anionic lipids, LPS) refer to Biological Roles and Reaction & Applications sections (general literature context).