CREKA peptide , CAS No.847058-45-1

CAS: 847058-45-1 Cat. No.: C1445754 Formule: C₂₃H₄₃N₉O₈S Poids moléculaire: 605.71

Storage

Store at -20°C

Shipped In

Ice chest + Ice pads

Vue d’ensemble

CREKA peptide is a short peptide sequence, belonging to self-assembling peptides (SAPs), which can self-assemble into functional nanostructures, typically nanofibers, under physiological conditions. CREKA peptide can be used to target tumor cells and tumor vasculature, exhibiting antitumor activity.

Spécifications

Conditions de stockage de stockage

Store at -20°C

Expédié en

Ice chest + Ice pads

Ce produit nécessite l'expédition en chaîne froide. Les services terrestres et autres services économiques ne sont pas disponibles.

Noms et identifiants

Poids moléculaire

605.71

Application Protocols

No tested application protocols, recommended dilutions, or validated methods are provided in the product data for this item. General guidance for peptide handling includes:

• Dissolution: Begin with sterile water or suitable buffer; if needed, add minimal DMSO to aid solubility before diluting into aqueous media.
• Filtration: For sterile applications, 0.22 µm filtration post-dissolution is common.
• Conjugation: Follow reaction guidelines in the Reaction Conditions tab, then purify by RP-HPLC or SEC and confirm by LC–MS.
• Controls: Include sequence-scrambled or blocked-thiol controls when probing thiol-dependent conjugation or binding phenomena.

For application-specific protocols (e.g., surface immobilization, nanoparticle conjugation, cell-based assays), develop method parameters empirically and refer to peer-reviewed literature. Always consult the CoA/SDS for any item-specific constraints.

Biological Roles

No item-specific biological claims are provided. The following points summarize literature-level information relevant to short peptides of the CREKA sequence without implying suitability for clinical use.

• General biochemical features (literature)

  • The sequence contains both basic (Arg, Lys) and acidic (Glu) residues, producing pH-dependent net charge and potential electrostatic interactions with polyanionic biomaterials.
  • The N-terminal cysteine introduces a thiol that can form disulfides or be used for site-specific conjugation to probes or carriers for in vitro studies.

• Reported roles (literature)

  • CREKA has been reported in the primary literature as a motif that can bind components of provisional extracellular matrices. Such reports describe interactions with fibrin/fibronectin-rich materials in experimental systems. These observations are context-dependent and require empirical validation in each assay.

• Biophysical considerations

  • Ionization of Arg/Lys side chains supports binding to negatively charged surfaces, membranes, or ECM mimetics in vitro.
  • Sequence-driven amphiphilicity is modest; aggregation is typically limited but can occur at high concentration or high ionic strength.

Important: This product is for research use only. No performance claims, target specificity, or biological efficacy are made in this listing. Users should design and validate experiments, including appropriate controls, consistent with their model systems.

Buffer Applications

While CREKA is not a buffer reagent, appropriate buffering is essential for peptide dissolution, storage, and conjugation.

• Dissolution and short-term handling (general/literature)

  • Typical buffers: water, PBS, HEPES, or phosphate buffer at pH 6.5–7.5. Mildly acidic solutions (e.g., 10–20 mM acetate, pH ~5–6) can improve initial dissolution without promoting thiol oxidation.
  • For thiol conjugations (maleimide–thiol), buffers at pH 6.5–7.0 (e.g., PBS or phosphate with 1–5 mM EDTA to chelate metals) help maintain thiol in reduced state and limit maleimide hydrolysis.

• Storage buffers (short-term)

  • Low-salt aqueous solutions at neutral to slightly acidic pH are commonly used. Inclusion of inert carriers (e.g., 0.1% BSA) can reduce adsorption to plastics in dilute solutions, if compatible with the application.

• Electrophoresis and analytics

  • For analytical RP-HPLC, water/acetonitrile with 0.05–0.1% TFA or formic acid is standard; for MS, formic acid is preferred over TFA.

• Practical notes

  • Filter sterilization (0.22 µm) after dissolution may be used for cell-adjacent workflows; confirm compatibility of any reducing agents or metals with downstream assays.

Item-specific pKa values or buffer capacity data are not provided; consult literature and adjust conditions to your assay’s requirements.

Green Alternatives

As a peptide, CREKA is inherently compatible with aqueous media, which aligns well with green chemistry principles that favor water as a solvent. Greener practice focuses on solvent minimization, benign reagents for conjugation, and energy-efficient handling.

• Solvent choices

  • Preferred: water, PBS, and other aqueous buffers at ambient temperature.
  • Reduce or avoid: high fractions of DMF, DMSO, acetonitrile where possible; if used for initial dissolution, promptly dilute into water.

• Greener coupling strategies (literature)

  • Use water-soluble carbodiimides (e.g., EDC) with NHS in buffered water to couple to carboxylates, avoiding chlorinated solvents.
  • Maleimide–thiol couplings can be performed in aqueous buffers (pH 6.5–7.0) without organic co-solvent.
  • Prefer TCEP (odorless, non-thiol) over DTT/β-mercaptoethanol to limit volatile sulfur compounds.

• Process and waste minimization

  • Prepare concentrated stocks and aliquot to minimize repeated thawing and waste.
  • Employ microscale conjugations with analytical confirmation (LC–MS) to reduce reagent consumption before scale-up.

Comparison (general)

• Aqueous peptide work versus organic solvent-heavy protocols: lower VOC emissions, improved operator safety, and simpler waste streams; tradeoffs include potential hydrolysis or oxidation in water and the need for careful pH control.

Item-specific stabilizers or green certifications are not provided; consult CoA if environmental or regulatory attributes are critical to your workflow.

Pharmaceutical Uses

This product is provided strictly for research use only. No pharmaceutical, clinical, or therapeutic uses are claimed or supported by this listing.

General formulation context for peptides (non-clinical, literature):

• Peptides are often formulated in aqueous buffers for preclinical research, with considerations for pH, ionic strength, and excipients to control adsorption and oxidation.
• Stabilization strategies may include lyophilization with cryo-/lyoprotectants (e.g., trehalose, mannitol) and oxygen minimization when free thiols are present.
• For conjugate preparation (e.g., peptide–dye, peptide–polymer), process development typically optimizes solvent composition, pH, and stoichiometry to achieve defined substitution levels.

Regulatory note: No pharmacopeial status, GMP grade, or clinical-grade specifications are provided for this item. If your work requires compliance with pharmacopeias (USP/EP/JP) or GMP, request appropriate documentation or select a product manufactured under those standards.

Physical Properties

Item-specific physico-chemical specifications are not provided in the 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.
• Molecular formula: Not specified for this item; refer to CoA/Spec Sheet.
• Melting point / boiling point: Not applicable to peptides in the conventional sense; peptides typically decompose before boiling (general statement).
• Density, refractive index: Not applicable/rarely defined for solid peptides (general statement).

General/literature guidance for small, water-compatible peptides like CREKA:

• Solubility (literature): often readily soluble in water, PBS, or dilute acids (e.g., 0.1% TFA or acetic acid) due to multiple ionizable residues (Arg, Lys, Glu). Solubility can be sequence- and salt-dependent. If needed, initial dissolution in minimal water or dilute acid, followed by buffer adjustment, is common practice.
• pI and charge state (literature): sequences containing Arg and Lys are cationic across a broad pH range; inclusion of Glu lowers net charge. The exact isoelectric point depends on terminal status and counterions.
• Hygroscopicity (literature): lyophilized peptides may be hygroscopic and can absorb moisture from air; handle quickly to minimize water uptake.

Important: For quantitative specifications (e.g., exact MW, purity, counterion content, residual solvents, water), this listing does not provide values. Consult the item’s CoA/Spec Sheet for definitive data.

Quality and Grades

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

Interpretation and practical implications (general for peptide products):

• Peptide purity (typical descriptors): Peptide listings commonly specify purity as percentage by HPLC (e.g., ≥95%, ≥98%). Higher purity reduces background in binding and imaging experiments and improves batch-to-batch reproducibility. Because purity is not provided here, confirm requirements with the CoA before critical experiments.
• Identity confirmation: Typically established by LC–MS and analytical HPLC chromatogram. If required, request supporting data such as HRMS, sequence confirmation, and counterion analysis.
• Counterions and form: Peptides are often supplied as trifluoroacetate (TFA) salts or acetate salts, which can influence mass and pH behavior. The counterion/form for this item is not specified; consult CoA.
• Modifications: Terminal capping (acetylation/amidation) or special protecting groups (e.g., Ac-, –NH2 C-terminus) significantly affect charge and solubility. No modifications are specified in the product data; verify termini and any special labels (e.g., FITC, biotin) on the CoA.
• Stabilizers and residuals: Stabilizers, residual solvents, and water content are not specified for this item. For sensitive applications (cell work, conjugation), review the CoA and consider pre-use dialysis or desalting if needed.

Reaction and Applications

Manufacturer applications are not provided for this listing; therefore, below are general, literature-based research uses and chemistries relevant to CREKA-like peptides.

• Conjugation and biorthogonal chemistry (literature)

  • The N-terminal cysteine enables chemoselective coupling via maleimide–thiol Michael addition, haloacetylation, or disulfide exchange for constructing peptide–dye, peptide–polymer, or peptide–nanoparticle conjugates.
  • Amine-functional residues (Lys side chain and N-terminus) allow NHS-ester coupling to carboxylates and isothiocyanate labeling under mild basic conditions.

• Materials and surface science

  • Immobilization onto gold or maleimide-functionalized surfaces for affinity capture or patterning, leveraging the cysteine thiol.
  • Incorporation into hydrogels or nanoparticles to introduce peptidic functionality (e.g., charge, binding motifs) for in vitro studies.

• Assay development

  • Use as a defined peptide standard or competitor in binding assays; cationic residues support electrostatic interactions with polyanionic matrices in model systems.

Practical tips

• Work freshly and under oxygen-minimized conditions to retain reduced thiol; include TCEP as a non-thiol reducing agent when disulfide suppression is critical (compatibility-dependent).
• Purify conjugates by RP-HPLC or SEC; confirm mass by LC–MS.

Note: Any biological targeting claims or specific in vivo applications are outside the scope of this product data and should be validated independently from primary literature.

Reaction Conditions

No item-specific reaction conditions are provided. Below are general, literature-based conditions for common transformations involving CREKA’s functional residues. Optimize empirically for your system.

• Thiol–maleimide conjugation

  • Buffer: 50 mM phosphate or PBS, pH 6.5–7.0; 1–5 mM EDTA to chelate metals.
  • Stoichiometry: 1.1–1.5 equiv maleimide per thiol for near-quantitative conversion.
  • Temperature/time: 20–25°C, 0.5–2 h; reaction is typically rapid. Avoid pH >7.5 to limit maleimide ring opening.

• EDC/NHS coupling (Glu carboxylate to amines)

  • Buffer: MES, pH 5.0–6.0 (avoid primary amines in buffer). Add NHS or sulfo-NHS to stabilize the intermediate.
  • Stoichiometry: 1.2–3 equiv EDC and NHS relative to carboxylate.
  • Temperature/time: 0–25°C, 0.5–4 h.

• NHS-ester labeling of Lys/N-terminus

  • Buffer: 50–100 mM bicarbonate or phosphate, pH 7.5–8.5 (no competing amines).
  • Stoichiometry: 1.1–3 equiv NHS-ester per reactive amine; control pH to bias N-terminus vs Lys.
  • Temperature/time: 0–25°C, minutes to 1 h; quench with Tris or ethanolamine.

• Maintaining reduced thiols

  • Use TCEP (0.2–2 mM) freshly; avoid excess that can reduce probes. Degas buffers and limit air exposure.

Reported yields and kinetics vary with substrates and matrices; verify by LC–MS and HPLC. These are general guidelines and not item specifications.

Safety and Handling

• Intended use: For research use only. Not for human or veterinary use.

• GHS classification and labeling

  • Signal word: Not specified for this item; refer to SDS.
  • Hazard statements (H-phrases): Not specified for this item; refer to SDS.
  • Pictograms: Not specified for this item; refer to SDS.

• General peptide handling guidance (professional/lab practice)

  • Avoid inhalation of powders and contact with skin/eyes; handle in a clean, dry environment, preferably in a fume hood or ventilated enclosure when weighing.
  • Personal protective equipment: lab coat, nitrile gloves, and safety glasses as minimum PPE. Consider dust mask/respirator if aerosolization could occur.
  • Solutions: prepare using clean, low-endotoxin water or appropriate buffers; filter sterilize if sterility is required for your application.
  • Incompatibilities: strong oxidizers can react with the cysteine thiol; avoid prolonged exposure to elevated pH or temperature which can promote deamidation (Asn/Gln; not present here) and thiol oxidation/disulfide formation. Metal ions can catalyze oxidation; use chelators if appropriate.
  • Thiol-specific notes: the N-terminal cysteine thiol can form disulfides upon air exposure. If free thiol is required, prepare solutions immediately before use, work under inert atmosphere when feasible, and/or include reducing agents compatible with your application.

• First-aid overview (general): In case of contact, rinse with water for 15 minutes; remove contaminated clothing. If inhaled, move to fresh air. If ingested, rinse mouth. Seek medical advice. Always consult the SDS for authoritative safety data.

Solvent Selection

CREKA is a short, generally water-compatible peptide; solvent choice is governed by ionizable side chains and the cysteine thiol.

• Polarity and miscibility (general/literature)

  • Primary solvents: water, PBS, and other aqueous buffers are typically suitable. Minimal volumes of dilute acids (e.g., 0.1% TFA or acetic acid) can aid initial dissolution, followed by pH adjustment.
  • Co-solvents: for challenging dissolutions, small fractions of DMSO or DMF can be used, then dilute immediately into aqueous media. Verify tolerance of downstream systems to organic cosolvents.

• Practical strategy

  • Start with nuclease-/endotoxin-free water at room temperature; gentle vortex/sonication helps.
  • If hydrophobic aggregation is observed, incrementally add DMSO (up to 5–10% v/v) or use buffered saline with low ionic strength.
  • To preserve a free thiol on Cys, avoid high pH and prolonged aeration; degassed buffers or inert atmosphere can limit oxidation.

• Comparison with alternatives

  • Compared to strongly hydrophobic peptides, CREKA typically requires less organic cosolvent due to the presence of Arg/Lys/Glu.
  • Compared to highly acidic peptides, CREKA dissolves at neutral pH with less need for base.

Item-specific solvent specs (solubility limits, pH stability range) are not provided here; consult the CoA/Spec Sheet for definitive numbers.

Storage and Reconstitution

• Storage conditions (item-specific)

  • Store at -20°C.
  • Shipped in: Ice chest + ice pads.

• Stability notes (general/literature)

  • Keep dry and protected from light and air to limit oxidation, especially of the N-terminal cysteine thiol.
  • For long-term storage, retain as a lyophilized powder when possible. Minimize headspace oxygen for re-sealed vials.

• Reconstitution (general guidance)

  • Use sterile, nuclease-/endotoxin-free water or an appropriate buffer. If necessary, initiate dissolution with a small volume of water or dilute acid (e.g., 0.1% acetic acid), then adjust to the desired buffer and pH.
  • If solubility is limited, add minimal DMSO, then dilute into aqueous media immediately.
  • To preserve a free thiol: prepare fresh solutions; consider degassed buffers and/or add compatible reducing agent (e.g., TCEP) as needed for your application.

• Aliquoting and freeze–thaw

  • Prepare single-use aliquots to avoid repeated freeze–thaw cycles.
  • Store aliquots at -20°C or below; avoid frost-free freezers that cycle temperatures.

Item-specific details such as exact solvent, concentration limits, and shelf life after reconstitution are not specified in this listing; refer to the CoA/Spec Sheet and your internal validation for final conditions.

Structure and Identity

CREKA peptide is a defined pentapeptide with the amino acid sequence Cys–Arg–Glu–Lys–Ala.

• Item-specific identifiers

  • CAS: 847058-45-1
  • Molecular formula: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular weight: Not specified for this item; refer to CoA/Spec Sheet.
  • SMILES: Not specified for this item; refer to CoA/Spec Sheet.
  • InChIKey: Not specified for this item; refer to CoA/Spec Sheet.
  • CID: Not specified for this item; refer to CoA/Spec Sheet.

• Sequence and structural features (general/literature description)

  • Primary structure: H–Cys–Arg–Glu–Lys–Ala–OH (free N-terminus and free C-terminus unless otherwise stated; item-specific terminal protections are not specified).
  • Functional groups: an N-terminal primary amine; a C-terminal carboxylic acid; side chains include thiol (Cys), guanidinium (Arg), carboxylate (Glu), primary amine (Lys), and a nonpolar methyl (Ala).
  • Ionization: polycationic at neutral pH when side chains are protonated; overall charge depends on pH and terminal protection (not specified for this item).
  • 2D description in words: a linear pentapeptide backbone with alternating amide bonds; the first residue bears a thiol-containing side chain suitable for chemoselective conjugation, followed by a basic guanidinium group, an acidic carboxylate, a basic ε-amine, and a small aliphatic methyl side chain.

• Stereochemistry (general): L-configuration at each alpha center is typical for synthetic bioactive peptides; configuration for this item is not specified—refer to CoA/Spec Sheet.

Synthetic Utility

CREKA serves as a versatile chemical handle in synthesis and bioconjugation due to its functional residue set and defined sequence.

• Functional group leverage

  • Cys (thiol): platform for thiol–maleimide conjugation, thioether formation with haloacetyls, native chemical ligation (NCL) when used with thioesters, and disulfide engineering.
  • Lys (ε-amine) and N-terminus: nucleophiles for NHS-ester coupling, isothiocyanates, and aldehyde-based reductive amination (after mild oxidation to generate an aldehyde on N-terminus if needed).
  • Glu (carboxylate): EDC/NHS-mediated coupling to amines in water.

• As a building block

  • Acts as a recognition motif that can be appended to polymers, nanoparticles, or surfaces to modulate charge and interactions in model systems.
  • Useful as a spacer or ligand in modular assembly strategies for biosensors or in vitro targeting constructs.

• Analytical confirmation

  • Reaction progress monitored by LC–MS (shift corresponding to conjugation mass), and by analytical RP-HPLC (retention time shift with increased hydrophobicity upon labeling).

• Protecting group strategy (SPPS context)

  • Typical Fmoc/tBu orthogonality: side-chain-protected CREKA can be assembled on solid support; free thiol is obtained after deprotection. For solution-phase work, transient protection of Cys (e.g., Acm, Trt) may be used to control chemoselectivity.

Item-specific protecting groups or modifications are not provided; refer to CoA for the supplied form.

Target Specificity

No target, antigen, or binding specificity is provided in the product data for SKU C1445754. This listing makes no claims regarding biological targets, receptor binding, or in vivo selectivity. If your application relies on a particular interaction, consult the primary literature and perform in-house validation under your assay conditions.

Foire aux questions

How should this product be stored?

Store at ?20 °C. Freezer storage is required to maintain the specified shelf life.

How is this product shipped?

This product ships in an insulated container with ice pads. Unpack on arrival and transfer it to the storage condition stated above.

What are the CAS number, molecular formula and molecular weight?

The CAS Number is 847058-45-1, the molecular formula is C23H43N9O8S, and the molecular weight is 605.71 g/mol.

What documentation is provided?

Available product documentation, including Certificates of Analysis (COA), Safety Data Sheets (SDS), and specification sheets, is shown in the product document area. Document availability and access follow the current site policy.