Alkyne Cholesterol , CAS No.1631985-09-5

CAS: 1631985-09-5 Cat. No.: A1440399 Summenformel: C₂₆H₄₀O Molekulargewicht: 368.60

Storage

Protected from light,Store at -20°C,Argon charged

Shipped In

Ice chest + Ice pads

Übersicht

Alkyne Cholesterol , a modified lipid, is a click chemistry reagent containing an alkyne group. The terminal alkyne group can be used in a highly specific linking reaction with azide-containing reagents in the presence of a copper (Cu)-containing catalyst. Alkyne Cholesterol can be used for tracking cellular cholesterol metabolism and localization.

Specifications

Storage

Protected from light,Store at -20°C,Argon charged

Verschickt in

Ice chest + Ice pads

Dieses Produkt erfordert Kühlkettenversand. Grundversand und andere Economy-Optionen sind nicht verfügbar.

Namen und Kennungen

Molekulargewicht

368.60

Application Protocols

Representative research workflows (general guidance; optimize for your system):

A. Preparation of alkyne cholesterol stock

• Under inert atmosphere, dissolve the compound at 10–50 mM in anhydrous DMSO or ethanol (or 10–25 mg/mL in CHCl3 for film methods). Filter through 0.22 µm PTFE if needed. Aliquot into amber vials, flush with argon, and store at −20 °C.

B. Liposome incorporation

• Combine phospholipids and alkyne cholesterol in CHCl3/MeOH (2:1 v/v) at desired mol%. Evaporate to a thin film, desiccate ≥1 h. Hydrate with buffer at temperature above lipid Tm, vortex, and sonicate or extrude to size. Click-label post-formation with azide probes in aqueous-organic CuAAC media.

C. Cell labeling (post-incubation click)

• Dose cells with alkyne cholesterol from DMSO/EtOH stock to a final organic content ≤0.5% v/v, optionally with carriers (e.g., cyclodextrins). Incubate to allow incorporation. Fix cells if desired, then perform CuAAC with azide-fluorophore using CuSO4/sodium ascorbate and a Cu(I)-stabilizing ligand in PBS containing 1–2% DMSO or t-BuOH. Wash thoroughly with chelators to remove copper.

D. Pull-down enrichment

• After incorporation, lyse samples, perform CuAAC with azide-biotin, remove copper, and capture on streptavidin resin. Wash, elute, and analyze by SDS-PAGE or LC–MS/MS.

Note: Adjust copper/ligand levels to minimize cytotoxicity for live-cell workflows. Always include appropriate controls with native cholesterol.

Biological Roles

General context (literature/general knowledge):

• Cholesterol is a fundamental component of eukaryotic membranes, modulating fluidity, permeability, and the formation of ordered microdomains. It influences endocytosis, receptor signaling microenvironments, and membrane protein function.
• Alkyne cholesterol is designed to mimic cholesterol’s amphipathic behavior while adding a minimally perturbing alkyne handle. It can incorporate into membranes and lipoproteins, enabling downstream tagging by CuAAC for imaging or enrichment.
• Applications include tracking cellular uptake and efflux pathways (e.g., interactions with transporters and lipid-transfer proteins), mapping sterol-rich domains, and studying cholesterol-dependent assembly of membrane proteins.
• In biochemical reconstitution, alkyne cholesterol can be doped into liposomes or nanodiscs to study sterol effects on membrane protein function while retaining the ability to append probes post-assembly.
• After incorporation, azide-bearing fluorophores or affinity tags can be ligated, allowing correlation of distribution with proteomic or lipidomic analyses. Careful controls with native cholesterol are recommended to verify that the alkyne modification does not alter the biological phenomenon under study.

Note: All uses are for research purposes only (per Product Data). No medical or clinical claims are made or implied.

Buffer Applications

This product is a hydrophobic sterol derivative and is not a buffering agent. It does not define pH ranges or buffering capacity. For experimental use, incorporate into organic solvent stocks or lipid films, then introduce into aqueous buffers via co-solvents, carrier systems (e.g., cyclodextrins), or lipid assemblies. Refer instead to the Solvent Selection and Application Protocols sections for practical handling guidance.

Green Alternatives

Context: Handling of alkyne cholesterol often involves chlorinated solvents and copper catalysts. Greener strategies can reduce environmental and safety burdens (literature/general knowledge).

Greener choices and trade-offs:

• Solvent substitution:
  • Replace DCM/CHCl3 with 2-methyltetrahydrofuran (2-MeTHF) or cyclopentyl methyl ether (CPME) where solubility allows; both offer improved safety and often enable efficient film formation and rehydration for liposomes.
  • Use ethanol or isopropanol as biocompatible carriers for cellular work at low percentages, minimizing DMSO or chlorinated solvent residues.
• Aqueous-compatible click:
  • Perform CuAAC in water-rich mixtures (e.g., t-BuOH/H2O, EtOH/H2O) using catalytic CuSO4/sodium ascorbate to lower organic solvent use. Employ ligand-accelerated systems (e.g., TBTA or water-soluble analogs) to improve efficiency at low copper loadings.
  • If copper sensitivity is an issue, consider strain-promoted azide–alkyne cycloaddition (SPAAC) using cyclooctyne-bearing partners; note that simple terminal alkynes require copper, so this alternative involves changing the azide partner to a strained alkyne reagent.
• Energy and waste:
  • Room-temperature reactions and short times reduce energy input.
  • Employ solvent recovery where feasible and use metal scavengers to minimize copper in waste streams.

Comparison snapshot:

• DCM/CHCl3: excellent solvency; higher toxicity and environmental impact.
• 2-MeTHF/CPME: greener profile; may require longer dissolution times or mild heating.
• EtOH/H2O CuAAC: greener medium; may reduce solubility for highly hydrophobic substrates—use surfactants/micelles as needed.

Pharmaceutical Uses

Item-specific pharmacopeial status/excipient grade: Not specified for this item; refer to CoA/Spec Sheet.

Research/formulation context (literature/general knowledge):

• Cholesterol is widely used as a functional excipient in liposomes and lipid nanoparticles to modulate membrane rigidity and permeability. Alkyne cholesterol extends this utility by enabling post-formulation functionalization through CuAAC with azide-bearing ligands (e.g., targeting peptides, PEG-azides, dyes) in research settings.
• Potential research applications include constructing ligand-decorated liposomes for receptor-binding studies, preparing pull-down compatible nanoparticles, or fabricating surfaces with immobilized sterol moieties for biophysical assays.
• Considerations: Copper residues from click reactions should be minimized in formulations intended for biological assays. Evaluate the effect of the alkyne substitution on membrane properties (e.g., Tm, leakage) relative to native cholesterol.

Note: Aladdin Scientific supplies this product strictly for research use only; it is not intended for human or veterinary use, clinical diagnostics, or as a GMP excipient.

Physical Properties

Item-specific values: Not specified for this item; refer to CoA/Spec Sheet.

General/qualitative properties for alkyne-tagged sterols (literature/general knowledge):

• Physical state: Typically a white to off-white waxy solid or foam at ambient temperature, similar to cholesterol derivatives.
• Solubility profile: Sparingly soluble in water; soluble in common organic solvents used for lipids (e.g., chloroform, dichloromethane, THF, ethyl acetate, toluene). Often soluble in polar aprotic solvents (DMSO) and lower alcohols (ethanol, isopropanol) to varying degrees depending on the alkyne placement.
• Amphipathicity: Retains a single polar 3β-hydroxyl headgroup and a large hydrophobic body, facilitating incorporation into lipid bilayers, liposomes, and micellar systems.
• Partitioning: Expected high logP consistent with sterols; the alkyne tag minimally perturbs hydrophobicity relative to cholesterol.
• Thermal behavior: Many sterols show gradual softening; discrete melting points can be sample- and purity-dependent. Use DSC to characterize phase transitions when formulating membranes.
• Spectroscopic features: Terminal alkyne C≡C stretch typically appears near ~2100–2150 cm−1 in IR (literature). 1H NMR shows a characteristic terminal alkyne proton near ~δ 2.0–2.5 ppm if present; 13C NMR for sp-carbons ~70–90 ppm (ranges depend on substitution).

Note: For exact BP/MP, density, refractive index, and water/peroxide/metal specs for SKU A1440399, consult the CoA/Spec Sheet.

Quality and Grades

Item-specific grade/purity: Not specified for this item; refer to CoA/Spec Sheet.

Guidance on quality considerations for lipid/sterol reagents (general knowledge):

• Purity impacts: Trace impurities (oxidized sterols, peroxides) can alter membrane behavior and confound trafficking studies. For quantitative biophysical work, choose material accompanied by HPLC/NMR purity data and a recent CoA.
• Water content: Moisture can affect dissolution and some coupling chemistries. Karl Fischer values, when available, help assess handling needs. For click chemistry, anhydrous stocks in dry DMSO or CHCl3/MeOH are preferred.
• Stabilization: Many lipid reagents are packaged under inert gas and protected from light (this item is Argon charged and light-protected). This minimizes autoxidation of allylic positions on the sterol core.
• Grades often encountered: “Research grade” lipids for discovery workflows; “HPLC grade” solvents for lipid handling; and in some cases, “BioReagent” grades with low fluorescent background for imaging applications. Select according to downstream analytical sensitivity (fluorescence, MS).
• Documentation: For SKU A1440399, consult Aladdin Scientific’s CoA/Spec Sheet for assay method, residual solvent limits, and any stabilizer information specific to this lot.

Reaction and Applications

Focus: The terminal (or internal) alkyne on the cholesterol scaffold enables bioorthogonal ligation and derivatization while preserving sterol-like biological partitioning (literature/general knowledge).

Key applications:

• Bioorthogonal labeling via CuAAC: Conjugate alkyne cholesterol with azide-tagged fluorophores, biotin, affinity handles, or polymers to visualize or enrich cholesterol-containing domains, lipoproteins, or reconstituted systems.
• Membrane trafficking studies: Incorporate into cell membranes or liposomes to track sterol distribution, raft association, and endocytic pathways using post-incubation click labeling.
• Proteomics/chemoproteomics: Metabolic incorporation followed by CuAAC-biotin ligation enables enrichment of sterol-binding proteins and analysis by LC–MS/MS.
• Materials and nanomedicine research: Introduce functional handles onto cholesterol-containing carriers (liposomes, lipid nanoparticles, sterol-modified polymers) for targeted delivery or surface functionalization.
• Surface and hydrogel modification: Embed in self-assembled systems where subsequent azide–alkyne ligation imparts stimuli-responsiveness or ligand display.

Practical tips:

• Maintain anhydrous stocks and protect from light and air; the allylic positions of sterols can oxidize over time.
• For cellular work, pre-complex with methyl-β-cyclodextrin or deliver via lipid carriers to enhance uptake; assess cytocompatibility of copper catalysts and consider post-fixation labeling where appropriate.
• Control stoichiometry in CuAAC to limit overfunctionalization. Remove copper after reaction (e.g., Chelex, EDTA washes) for sensitive assays.
• Validate incorporation by thin-layer chromatography (TLC), LC–MS, or fluorescence after click conjugation.

Reaction Conditions

General literature guidance for typical reactions involving alkyne cholesterol:

CuAAC (azide–alkyne click):

• Solvent: t-BuOH/H2O (1:1), EtOH/H2O, or DMSO/H2O; for hydrophobic substrates, add surfactant or use micellar media, or pre-solubilize in minimal DMSO.
• Catalyst system: CuSO4 (0.5–5 mol%) with sodium ascorbate (1–10 equiv vs Cu) to generate Cu(I) in situ; accelerate with tris(triazolylmethyl)amine ligands (e.g., TBTA, BTTAA). Room temperature to 40 °C.
• Stoichiometry: 1.0–1.5 equiv azide relative to alkyne. Reaction times: 0.5–16 h depending on dispersion and ligand.
• Workup: Chelate/remove copper (e.g., EDTA washes, metal scavengers), extract into organic solvent, or purify by silica gel (use copper-scavenging stationary phases if needed).

Thiol–yne additions:

• Initiation: Photoinitiated (e.g., 365–405 nm with Type I photoinitiator) or radical initiators (AIBN) in degassed solvents (THF, toluene). Typical temperatures: ambient to 60 °C. Monitor to avoid double addition if mono-addition is desired.

Formulation incorporation:

• Lipid film hydration: Dissolve components in CHCl3/MeOH, rotary-evaporate to a film, desiccate, then hydrate above the highest Tm of components with buffer; apply sonication or extrusion.

Note: Parameters are representative literature ranges and should be optimized empirically for specific azides, solvents, and assemblies. Always consult primary references for your exact system.

Safety and Handling

Item-specific hazard classifications: Not specified for this item; refer to SDS for authoritative information.

• Signal Word: Not specified for this item; refer to SDS.
• H-Statements/GHS Classification/Pictograms: Not specified for this item; refer to SDS.

General safety guidance for sterol derivatives with alkyne tags (literature/general knowledge):

• Expected hazards: Low volatility solid; may cause skin/eye/respiratory irritation. Avoid dust generation. Handle as a laboratory chemical of unknown toxicity.
• PPE: Wear lab coat, safety glasses, and appropriate chemically resistant gloves (e.g., nitrile). Use in a fume hood when weighing/dissolving, especially when employing organic solvents or copper catalysts for click reactions.
• Incompatibilities: Strong oxidizers may react with organic compounds; avoid contact with strong acids/bases that can cause dehydration or esterification of the 3β-OH. Copper-catalyzed reactions require control of adventitious oxidants to limit oxidative byproducts.
• First aid (overview): Eye/skin contact—rinse with water for at least 15 minutes; remove contaminated clothing. Inhalation—move to fresh air. Ingestion—rinse mouth; seek medical advice. Always consult the SDS for detailed procedures.
• Waste: Dispose according to institutional and local regulations for organic chemical waste. If used with copper catalysts or azides, segregate waste as appropriate (heavy metal-containing waste, energetic azides policy).

Research use: For research use only (per Product Data).

Solvent Selection

Applicability: As a hydrophobic sterol derivative, solvent choice governs successful dissolution, handling, and formulation.

General guidance (literature/general knowledge):

• Preferred solvents for stock solutions: chloroform, dichloromethane, THF, toluene, ethyl acetate. Polar options include dry DMSO or ethanol/isopropanol for biochemical workflows. Water solubility is negligible; use co-solvents or carriers.
• Lipid film method: Dissolve in CHCl3 or CHCl3:MeOH (2:1 v/v), evaporate to a thin film, then hydrate above the lipid’s transition temperature to prepare liposomes or mixed membranes.
• Aqueous delivery: For live-cell labeling, prepare a concentrated DMSO or ethanol stock (e.g., 10–50 mM, as solubility allows) and deliver at ≤0.5% v/v organic to media, often with carrier proteins or cyclodextrins for improved uptake.
• CuAAC media: For click conjugation, t-BuOH/H2O, MeOH/H2O, or DMSO/H2O mixtures solubilize both alkyne cholesterol and azides; surfactants or micelles can aid dispersion in biphasic systems.

Comparison considerations:

• Chloroform: excellent solubilizer for lipids; volatile/toxic; handle in hood.
• DMSO: biocompatible at low %; high boiling; may complicate drying.
• Ethanol: compatible with cells at low %; lower solubility than chlorinated solvents.
• 2-MeTHF or CPME: greener alternatives to DCM/THF with good lipid solvation; verify solubility experimentally.

Storage and Reconstitution

Item-specific storage and shipping (from Product Data):

• Storage conditions: Store at −20 °C, protected from light, Argon charged.
• Shipping: Ice chest + ice pads.

Best practices (general guidance):

• Upon receipt, allow container to equilibrate to room temperature in a desiccator before opening to minimize moisture condensation. Open under inert atmosphere if possible.
• Aliquot into small amber vials to avoid repeated freeze–thaw and headspace oxygen. Maintain an inert gas blanket (argon or nitrogen) after each use.
• Solvent recommendations: Prepare concentrated stocks in anhydrous CHCl3, DCM, THF, toluene, ethanol, or DMSO depending on application. For biological assays, DMSO or ethanol stocks are convenient; filter sterilize if required by workflow.
• Stability considerations: Protect from light and air to limit autoxidation of sterol moieties. Avoid strong acids/bases and prolonged heating.
• Reconstitution for formulations: For liposomes or mixed membranes, dissolve with other lipids in CHCl3/MeOH, form a thin film, and hydrate as per protocol. For aqueous systems, introduce via co-solvent at low percentages or using carriers (e.g., cyclodextrins).

Note: For exact shelf-life, assay specifications, and any stabilizers present for SKU A1440399, refer to the lot-specific CoA/Spec Sheet and SDS.

Structure and Identity

Item-specific identifiers from Product Data:

• CAS: 1631985-09-5
• 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.

General structural description (literature/general knowledge):

• Alkyne cholesterol denotes a cholesterol scaffold (perhydrocyclopentanophenanthrene tetracyclic sterol core with a 3β-hydroxyl) bearing a terminal or internal alkyne tag on a side chain position. The alkyne serves as a bioorthogonal handle for Cu-catalyzed azide–alkyne cycloaddition (CuAAC) labeling.
• Key functional groups: secondary alcohol (3β-OH), multiple trans-fused rings, isooctyl-like side chain derivatized to include an alkyne. The alkyne is sp-hybridized carbon–carbon triple bond capable of click chemistry and other alkyne transformations.
• Stereochemistry: Cholesterol possesses multiple defined stereocenters (e.g., 3β-OH orientation and ring junction stereocenters). The alkyne substitution typically preserves the native cholesterol stereochemistry at ring junctions.
• 2D description: A rigid four-ring backbone with a polar 3β-OH at one end and a hydrophobic side chain terminated or interrupted by an alkyne moiety, yielding an amphipathic molecule suitable for membrane incorporation and subsequent conjugation.

Synthetic Utility

Functional handle: The terminal/internal alkyne appended to the cholesterol side chain enables modular derivatization while maintaining a sterol framework (literature/general knowledge).

Transformations:

• Cu-catalyzed azide–alkyne cycloaddition (CuAAC): efficient formation of 1,4-disubstituted triazoles with azide reagents, allowing attachment of fluorophores, biotin, PEG, peptides, or affinity tags.
• Alkyne additions: Hydrosilylation, hydroboration, and thiol–yne click can be used to install diverse substituents; reaction conditions should preserve the sterol core and 3β-OH.
• Oxidation/esterification at 3β-OH: Independent of the alkyne, the sterol alcohol can be esterified (e.g., carbonate formation) to generate pro-forms or anchors.
• Cross-couplings: If the alkyne is terminal, Sonogashira coupling after halogenation is conceptually possible but less common on the sterol substrate; protecting groups may be necessary.

Utility in assembly:

• Acts as a bifunctional building block for constructing sterol-decorated polymers, lipids, or surfaces; incorporation into block copolymers imparts membrane-associating characteristics plus a conjugation handle.

Tips:

• Use anhydrous, oxygen-limited conditions for alkyne reactions to suppress oxidative side products. Monitor reactions by TLC (staining with phosphomolybdic acid or anisaldehyde) and confirm by NMR/MS. Avoid strong acids/bases that may rearrange sterol skeletons.

Target Specificity

Not applicable to this product. Alkyne cholesterol is a small-molecule sterol derivative and does not possess antigen/epitope specificity, clone identity, or species reactivity attributes associated with biological affinity reagents. For use-cases involving selective labeling, specificity is dictated by the choice of azide-tagged partner (e.g., ligand, fluorophore) and the biological system studied.

Häufig gestellte Fragen

How should this product be stored?

Store at ?20 °C, protected from light, under argon. It is supplied under an argon blanket; reseal under inert gas after each use.

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 1631985-09-5, the molecular formula is C26H40O, and the molecular weight is 368.60 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.