Iodo-PEG12-NHS ester , CAS No.I1447358

CAS: I1447358 Cat. No.: I1447358 분자식: C₃₁H₅₆INO₁₆ 분자량: 825.68

Storage

Store at -20°C

Shipped In

Ice chest + Ice pads

개요

Iodo-PEG12-NHS ester is a PEG-based PROTAC linker that can be used in the synthesis of PROTACs.

Specifications

보관 조건

Store at -20°C

배송

Ice chest + Ice pads

이 제품은 콜드 체인 배송이 필요합니다.지상 및 기타 경제 서비스는 사용할 수 없습니다.

이름과 식별자

분자량

825.68

Application Protocols

No manufacturer-verified protocols are provided for this specific SKU. The following general workflow illustrates typical usage; adjust to your system.

Example: Two-step protein conjugation

1. NHS–amine coupling

• Prepare a 10–50 mM stock in anhydrous DMF or DMSO.
• Exchange protein into 50 mM phosphate buffer, pH 7.8 (amine-free), 0.15 M NaCl.
• Add linker stock to achieve 3–10 molar equivalents per protein amine target; incubate 30–60 min at room temperature.
• Quench with 20 mM ethanolamine, 10 min.
• Desalt (spin column) into neutral buffer lacking reducing agents.

2. Thiol capture via iodo terminus

• Ensure target thiols are available (pre-reduce with TCEP if necessary, then remove TCEP).
• Combine modified protein with thiol-bearing partner (1–5 equiv per iodide), pH 7.0–7.5, 30–90 min.
• Purify by size-exclusion or affinity chromatography.

Controls and QC

• Run no-linker and quenched-linker controls.
• Confirm modification by intact MS and/or peptide mapping; assess functional activity of the conjugate.

Note: For research use only; no diagnostic or therapeutic procedures are implied.

Biological Roles

This molecule has no endogenous biological role; it is a synthetic crosslinker for research applications.

• Functional role in bioconjugation (general)
  • The NHS ester end selectively acylates primary amines on biomolecules (e.g., lysines), generating stable amide linkages.
  • The iodo terminus provides a soft electrophile suitable for selective reaction with thiols, enabling site-preferential modification of cysteine residues under mild conditions.
  • The PEG12 spacer improves aqueous compatibility, reduces protein–protein interactions, and can mitigate immunogenic epitopes or aggregation relative to shorter, hydrophobic linkers.
• Use cases in biochemical workflows
  • Constructing well-defined protein–ligand and protein–polymer conjugates.
  • Tethering molecules to surfaces (beads, nanoparticles) bearing amine or thiol functionalities.
  • Creating precursors for orthogonal chemistry: the iodo group can be transformed (e.g., to azide) after amine coupling, enabling subsequent click ligations.
• Considerations
  • Reaction conditions should preserve biological activity of the partner biomolecule (neutral pH, low organic fraction, short reaction times).
  • Buffer components containing free amines or thiols must be excluded to maintain selectivity.

Note: For research use only. No clinical or in vivo performance is claimed or implied.

Buffer Applications

As a reactive crosslinker, this product is not used to prepare buffering systems, but buffer choice critically impacts conjugation outcomes.

• Recommended buffers for NHS–amine coupling
  • Phosphate buffer (50–100 mM, pH 7.4–8.0): good general choice; lacks primary amines.
  • Bicarbonate/Carbonate buffer (50–100 mM, pH 8.3–8.5): increases amine nucleophilicity; faster coupling but more hydrolysis.
  • HEPES/MOPS/MES: zwitterionic buffers are acceptable if pH is in 7.0–8.5 and no amines are present.
• Buffers/additives to avoid
  • Tris, glycine, ammonium salts, primary/secondary amine-containing components: they quench the NHS ester.
  • Thiol reagents (DTT, βME): they react with the iodo group; use TCEP only for pre-reduction and remove prior to conjugation.
• Practical recipes (example guidance)
  • Phosphate buffer: 10 mM Na2HPO4, 150 mM NaCl, pH 7.8 (omit amines/thiols). Prepare fresh and degas if needed.
  • Carbonate buffer: 50 mM NaHCO3/Na2CO3, pH 8.3. Use promptly to limit hydrolysis.
• Co-solvent use
  • Add 5–20% anhydrous DMF or DMSO to improve linker solubility while keeping the aqueous majority to protect biomolecule structure.

Always verify compatibility with the target biomolecule (stability, activity) before scale-up.

Green Alternatives

While the linker itself is fixed, greener choices can be made for solvents and process design.

• Greener solvent options (informational)
  • Replace a portion of DMF with acetonitrile or ethanol/water cosolvents for short exposures; ensure rapid use to limit NHS hydrolysis.
  • Propylene carbonate (PC) can solubilize many PEG linkers and offers a greener profile than DMF; verify solubility/reactivity for your system.
  • Limit DMSO volumes to what is strictly necessary; consider ACN as a less toxic alternative when adequate solubility is achieved.
• Process intensification
  • Perform reactions at higher concentrations to reduce solvent use, provided aggregation is not an issue.
  • Use in situ desalting (spin columns) to minimize buffer volumes and waste during bioconjugation workflows.
• Comparative notes (general)
  • DMF: excellent performance but poor EHS profile.
  • DMSO: broadly acceptable; persistent in wastewater.
  • ACN: more volatile, recyclable by distillation; toxicity still requires controls.
  • PC: low vapor pressure, good safety; higher viscosity can slow mixing.

Trade-offs

• NHS esters demand low-water conditions; greener aqueous media increase hydrolysis. A pragmatic approach is to prepare concentrated anhydrous stocks, then perform brief, small-volume aqueous conjugations followed by immediate workup to limit waste and degradation.

Pharmaceutical Uses

No pharmacopeial status or excipient designation is provided for this item; it is supplied for research use only.

• Typical roles in drug discovery workflows (non-clinical)
  • Construction of antibody–drug conjugate (ADC) prototypes and other bioconjugates during screening and method development.
  • Preparation of PEGylated intermediates to assess PK/PD impacts in preclinical research (without implying clinical suitability).
  • Surface functionalization of particles or devices for assay development and analytical method qualification.
• Manufacturing/CMC considerations (general)
  • For any movement toward regulated use, one typically requires detailed impurity profiles, residual solvent limits, elemental analysis, and validated analytical methods for active ester content—none are specified here; consult CoA/Spec Sheet.
  • Batch-to-batch PEG dispersity and identity of the iodinated terminus must be tightly controlled; demonstration of robust stability under proposed storage is essential.

Important: Aladdin Scientific supplies this material strictly for laboratory research. It is not intended for human or veterinary use, and no claims are made regarding clinical safety, efficacy, or GMP suitability.

Physical Properties

Only limited item-specific data are provided for this product. Do not treat the following as product specifications.

• 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 specified for this item; refer to CoA/Spec Sheet.
• Density, refractive index, UV cutoff: Not specified for this item; refer to CoA/Spec Sheet.

Literature/general behavior for NHS–PEG linkers (informational):

• PEG12 spacers typically impart good solubility in polar aprotic solvents (DMF, DMSO, acetonitrile) and miscibility with aqueous buffers when diluted from an anhydrous stock.
• The iodinated terminus is a good leaving group; the NHS ester is moisture-sensitive and undergoes hydrolysis to the corresponding carboxylic acid in water.
• Estimated end-to-end linker length for PEG12 is often cited as approximately 4.8–5.4 nm (literature, conformation-dependent).
• pKa: Not applicable (no classical acid/base handle aside from the activated ester, which is not titratable in the usual sense).
• LogP: Context-dependent due to PEG; overall behavior is amphiphilic with enhanced hydrophilicity versus purely alkyl linkers.

Note: Consult the item’s CoA/Spec Sheet for any measured values specific to this batch.

Quality and Grades

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

General guidance for interpreting quality on NHS–PEG linkers:

• Purity percentage (when provided) reflects organic purity by NMR/LC-MS/HPLC; trace hydrolysis to the non-reactive acid may occur if handled improperly.
• Functional content: Effective % of active NHS ester is critical. Even with high chromatographic purity, functional activity can decrease via hydrolysis; recent CoA is recommended.
• Water content/residual solvents/UV specs: Not specified for this item; refer to CoA/Spec Sheet for limits relevant to sensitive bioconjugations.
• Stabilizers: NHS esters typically do not include stabilizers; shelf life is driven by moisture exclusion and low-temperature storage.

Practical implications:

• Request a fresh CoA to confirm active ester content before critical conjugations.
• Perform a small pilot coupling (e.g., with an amine standard) to validate reactivity when reaction performance is crucial.
• If UV purity is important (e.g., for downstream analytics), select lots with documented low-UV background and confirm by blank runs.

Note: This product is designated “For research use only.” It is not certified for diagnostic or therapeutic applications.

Reaction and Applications

Iodo-PEG12-NHS ester is a classic heterobifunctional crosslinker for sequential, chemoselective bioconjugations.

• Primary amine coupling (NHS end)
  • Reacts with primary aliphatic amines (lysine side chains, N-termini, amine-bearing ligands) to form stable amide bonds.
  • Optimal in pH 7.5–8.5 buffers lacking competing amines (avoid Tris/glycine). Reaction proceeds via acyl substitution with NHS as leaving group.
• Iodinated electrophile coupling (iodo end)
  • The iodo terminus is a soft electrophile, facilitating SN2 with thiols to give thioethers; it can also react with other nucleophiles (e.g., azide, amines) under appropriate conditions.
  • Common use: install the linker onto an amine-bearing biomolecule first, then capture a free thiol partner (e.g., cysteine on proteins or thiolated oligos) to complete the conjugation.
• Spacer advantages (PEG12)
  • Enhances water compatibility and reduces steric hindrance, improving conjugation efficiency and preserving biomolecule function by distancing the payload.
• Typical applications
  • Protein–hapten, protein–polymer, and nanoparticle surface modification.
  • Introduction of a PEG12 handle with a terminal iodo group for subsequent substitution to azide/thiol/amine handles, enabling modular orthogonal chemistries (e.g., copper-free click after azide installation).
• Practical tips
  • Use fresh stocks and exclude moisture; NHS esters hydrolyze rapidly.
  • Control stoichiometry to minimize over-modification; quench unreacted NHS ester with ethanolamine if needed after the first step.
  • For thiol coupling, maintain thiols in reduced form (avoid DTT/βME during reaction; use TCEP pre-reduction followed by desalting).

Reaction Conditions

Guidance below reflects common literature practice for NHS–amine couplings and iodide substitutions; adjust to your system. These are not product specifications.

• Amine coupling (NHS ester)
  • Solvent/buffer: 10–50 mM phosphate or bicarbonate, pH 7.5–8.5; 0–20% DMF/DMSO co-solvent.
  • Temperature/time: 20–25°C for 30–120 min; longer times increase hydrolysis.
  • Stoichiometry: 1.1–10 equiv linker per primary amine (protein labeling often 3–10 equiv per target lysine count).
  • Quench: ethanolamine (10–50 mM) after reaction to cap residual NHS ester.
• Thiol alkylation at the iodo end
  • Buffer: neutral pH (7.0–7.5) to maintain thiolate while protecting protein integrity; include 1–10 mM EDTA to suppress metal-catalyzed side reactions.
  • Reducing conditions: pre-reduce disulfides with TCEP, then remove excess before coupling; avoid free DTT/βME during reaction.
  • Time/temp: 30–120 min at 20–25°C; optionally add mild base (e.g., 10–50 mM bicarbonate) to increase thiolate formation.
• Alternative substitutions (small-molecule context)
  • Azidation: NaN3 (1.5–3.0 equiv) in DMF or DMSO, 25–50°C, 1–6 h (literature generality for iodoalkyls); monitor by LC-MS.
  • Amination: Primary/secondary amines (2–5 equiv) with base (e.g., DIPEA) in DMF/ACN, 25–60°C.
• Workup and analysis
  • Rapid desalting or spin-column cleanup after aqueous steps minimizes hydrolysis.
  • Track conversions by LC-MS; for proteins, use intact MS and peptide mapping where feasible.

Note: Half-life of NHS esters in aqueous buffers is typically tens of minutes to a few hours at pH 7.5–8.5 (literature), emphasizing the need for prompt handling.

Safety and Handling

• GHS/Classification: Not specified for this item; refer to SDS for authoritative hazard information.
• Signal word / H-statements / pictograms: Not specified for this item; refer to SDS.

General safety considerations for NHS esters and iodinated linkers (informational):

• Hazards
  • Irritation: NHS esters can be skin/eye/respiratory irritants; iodinated organics may be harmful if swallowed or inhaled.
  • Sensitization: Protein-reactive NHS esters may cause allergic skin reactions in susceptible individuals.
  • Hydrolysis: Moisture deactivates the NHS ester; avoid exposure to humid air.
• PPE and engineering controls
  • Wear lab coat, safety glasses, and nitrile gloves; handle powders/solids in a fume hood to avoid inhalation.
  • Use anhydrous technique; keep containers tightly closed under dry inert gas when possible.
• Incompatibilities and conditions to avoid
  • Avoid water, alcohols, and amine-containing buffers during storage and stock preparation; these accelerate hydrolysis/consumption.
  • Strong bases or nucleophiles will react with either end of the molecule; avoid unintended contact.
  • For working solutions, avoid thiol- and amine-containing additives (e.g., Tris, glycine, DTT, βME) unless they are the intended reactants.
• First aid (overview; defer to SDS)
  • Skin/eye contact: Rinse with water for 15 minutes; remove contaminated clothing; seek medical attention if irritation persists.
  • Inhalation: Move to fresh air; seek medical attention if symptoms occur.
  • Ingestion: Rinse mouth; do not induce vomiting; obtain medical attention.

Always consult the current SDS for definitive guidance.

Solvent Selection

Selecting solvents for Iodo-PEG12-NHS ester must balance solubility with preservation of the reactive NHS ester.

• Polarity and miscibility (general behavior)
  • Highly soluble in polar aprotic solvents: dry DMF, DMSO, and acetonitrile commonly provide clear stocks at 5–100 mM.
  • Partially miscible with water due to PEG12, but NHS ester will hydrolyze; use aqueous media only after rapid dilution into target buffer for immediate coupling.
  • Limited solubility expected in nonpolar solvents (e.g., hexanes); moderate in ethyl acetate and alcohols, though alcohols can slowly react.
• Recommended choices by use case
  • Stock preparation: anhydrous DMF or DMSO; optional co-solvent ACN to reduce viscosity.
  • Bioconjugation to amines: dilute the anhydrous stock into pH 7.5–8.5 amine-free buffer (e.g., phosphate or bicarbonate) immediately before use.
  • Thiol alkylation at the iodo end: conduct in buffered aqueous/organic mixtures (e.g., PBS or HEPES with 5–20% DMF/DMSO) at neutral pH to maintain thiols and minimize competing hydrolysis.
• Comparison (informational)
  • DMF: maximal solubility, easy handling; higher toxicity.
  • DMSO: very convenient; can participate weakly in side reactions at high pH—keep neutral to slightly basic.
  • ACN: lower viscosity, faster mixing; moderate solubility.

Always prepare fresh, anhydrous stocks; limit aqueous exposure to the shortest feasible time.

Storage and Reconstitution

• Storage conditions (item-specific)
  • Store at −20°C. Provided shipping: Ice chest + ice pads.
• Additional handling guidance (general best practice for NHS esters)
  • Keep desiccated and protect from ambient moisture; consider storage under inert gas.
  • Minimize light exposure for iodinated compounds; use amber vials when possible.
  • Avoid repeated freeze–thaw; prepare single-use aliquots upon first opening.
• Reconstitution
  • Dissolve in anhydrous DMF or DMSO to 10–100 mM. Filter (0.2 µm PTFE) if particulates are present.
  • Use immediately or aliquot and refreeze at −20°C. Clearly label date and concentration.
• Working solutions
  • Dilute stocks into amine-free buffers (pH 7.5–8.5) immediately before use for NHS coupling. Limit aqueous exposure time to curb hydrolysis.
  • For thiol reactions at the iodo end, use neutral buffers (pH 7.0–7.5) and avoid added thiols/reducing agents unless they are the intended reactants.
• Stability notes
  • Active ester content declines with moisture and elevated temperature. Assess reactivity if material has been warmed or stored long-term.

For any lot-specific stability or assay details, consult the CoA/Spec Sheet and SDS.

Structure and Identity

Iodo-PEG12-NHS ester is a heterobifunctional PEG linker combining an N-hydroxysuccinimide (NHS) activated ester with an iodinated electrophile, separated by a polyethylene glycol spacer of approximately 12 ethylene glycol units.

• Item-specific identifiers
  • CAS: I1447358 (catalog placeholder)
  • 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.
• Structural features (general/literature description)
  • One terminus bears an NHS-activated carboxylate (succinimidyl ester) designed to acylate primary amines to form stable amide bonds.
  • The opposite terminus contains an iodinated alkyl electrophile (commonly iodoacetyl or ω-iodoalkyl in related products) enabling SN2/S-alkylation with thiols or other soft nucleophiles.
  • The PEG12 spacer comprises ~12 –O–CH2–CH2– repeats, conferring water compatibility, reduced nonspecific binding, and increased solubility relative to purely hydrophobic linkers.
  • Overall, the molecule is linear, flexible, and amphiphilic; it is not chiral and lacks aromatic rings except for the succinimide moiety.
• 2D structure in words (general)
  • Succinimide leaving group attached to a carbonyl (activated ester) – followed by a twelve-unit ethylene glycol chain – ending in an iodinated terminal carbon. This creates an amine-reactive end and an iodide-leaving group end for sequential conjugations.

Synthetic Utility

Iodo-PEG12-NHS ester is a versatile building block for modular synthesis and surface chemistry.

• Orthogonal reactivity
  • NHS ester → amide formation with primary amines provides a robust anchor to small molecules, peptides, proteins, or surfaces bearing –NH2.
  • Iodide terminus → SN2 handle for introduction of diverse nucleophiles (RS−, N3−, NR2, etc.). Conversion to azido-PEG12 enables downstream click ligations (CuAAC/SPAAC) after amide installation.
• Retrosynthetic planning
  • Use it to graft a hydrophilic PEG12 spacer onto hydrophobic scaffolds, tuning solubility/permeation without altering the core pharmacophore.
  • Install the PEG12 first via amide to a solid support or small molecule, then diversify the distal iodide to generate libraries (e.g., thioethers, tertiary amines, quaternary ammonium salts).
• Surface and polymer modification
  • Activation of amine-rich surfaces (polylysine, aminated silica, beads) followed by iodide substitution to tether thiol- or azide-bearing ligands.
• Practical considerations
  • Sequence reactions to exploit chemoselectivity: complete amine coupling under mildly basic, dry conditions, then purify/desalt before nucleophilic substitution at the iodide.
  • Monitor each step by LC-MS or MALDI to confirm retention of PEG chain length and successful transformations.

This linker streamlines access to PEGylated analogs while maintaining late-stage diversification flexibility.

Target Specificity

Not applicable to this chemical linker. No antibody/biological target, clone, isotype, or species reactivity is defined for this item. Conjugation selectivity arises from functional-group chemistry (primary amines for the NHS ester; thiols and other soft nucleophiles for the iodide), not from biological recognition.