NHS PEG COOH - MW 5000 Da

Cat. No.: N164050

GRADE & PURITY MW 5000 Da

Storage

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

Shipped In

Ice chest + Ice pads

개요

Heterobifunctional PEG derivative that can be used to modify proteins, peptides and other materials via amino or other acid reactive chemical groups. PEGylation can increase solubility and stability and reduce immunogenicity of peptides and proteins. It can also suppress the non-specific binding of charged molecules to the modified surfaces.

Specifications

사양 및 순도

MW 5000 Da

보관 조건

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

배송

Ice chest + Ice pads

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

화학 및 물리적 특성

• 용해성: Off-white/white solid or viscous liquid depends on molecule weight;Soluble in regular aqeous solution as well as most organic solvents
• 감도: Light sensitive

Application Protocols

The following are general, literature-based protocols for using NHS PEG COOH in research labs. Adjust for substrate, PEG molecular weight, and desired degree of labeling.

Protocol A: Amine coupling in mixed aqueous media (proteins/biomolecules)

1. Prepare target in amine-free buffer (e.g., 50 mM phosphate or HEPES, pH 7.2) at 1–10 mg/mL.
2. Dissolve NHS PEG COOH freshly in dry DMSO at 50–200 mM.
3. Add linker solution dropwise to the stirred protein to 2–10 molar equiv per accessible amine (or 2–20 equiv per protein; optimize).
4. React 30–60 min at 20–25°C. Avoid >10% v/v DMSO.
5. Quench unreacted NHS with 20–50 mM ethanolamine or glycine (15 min).
6. Purify by desalting (e.g., Sephadex G-25) or spin filtration (MWCO selected to retain conjugate).

Protocol B: Surface amination conjugation (organic)

1. Dry amine-functionalized substrate thoroughly.
2. In dry DMF, combine substrate with NHS PEG COOH (10–50 mM) and DIPEA (2–3 equiv vs. surface amine estimate).
3. Agitate at RT for 1–4 h under inert atmosphere.
4. Rinse with DMF, then IPA, then buffer. Verify modification by appropriate surface assay.

Protocol C: Secondary activation of terminal –COOH (aqueous EDC/NHS)

1. Suspend NHS-PEGylated intermediate in MES buffer (0.1 M, pH 5.5–6.0).
2. Add EDC (1–2 equiv) and NHS (1–2 equiv); incubate 10–20 min.
3. Introduce amine-bearing ligand in buffer pH 7.2–7.4; react 1–2 h.
4. Purify as needed.

Note: These are general guidelines; no item-specific, validated application data are provided.

Biological Roles

NHS PEG COOH is not a natural metabolite; it is a synthetic linker used to modulate biomolecular interfaces.

General/literature context (no clinical claims):

• PEGylation/spacer function: The PEG chain imparts hydrophilicity and conformational flexibility, increasing effective solubility of attached ligands and reducing nonspecific interactions in assays and on surfaces.
• Selective reactivity: The NHS ester targets primary amines (e.g., lysine side chains), enabling site-scattered labeling of proteins or amine-bearing biomaterials. The terminal –COOH remains available for subsequent activation to couple additional moieties (e.g., peptides, dyes, haptens) via carbodiimide chemistry.
• Biointerface engineering: PEG segments are widely used to create protein-resistant layers and to define inter-ligand distances on nanoparticles/microbeads, which can influence binding avidity and steric accessibility in biochemical assays (literature).
• Stability considerations in biological media: NHS groups hydrolyze in aqueous buffers, especially at pH > 7.5, producing the non-reactive acid and NHS byproduct; timing, pH, and reagent excess are therefore critical to achieve desired degrees of labeling.

These roles are methodological and applicable to in vitro research and analytical development; this product is designated "For research use only" per the product data.

Buffer Applications

This product is not a buffering agent. However, buffer selection is critical for successful NHS–amine coupling using NHS PEG COOH.

Practical buffer guidance (literature):

• Avoid amine-containing buffers (e.g., Tris, glycine) during coupling; they compete with target amines and quench the NHS ester.
• pH considerations: pH 6.0–7.4 balances amine nucleophilicity and NHS stability. Higher pH accelerates reaction but also hydrolysis; optimize empirically.
• Common choices:
  • MES (50–100 mM, pH 5.5–6.5): Maximizes NHS stability; useful for surface conjugations where reaction times are longer.
  • PBS or phosphate buffer (10–50 mM, pH 7.0–7.4): Good compromise for many protein conjugations; watch hydrolysis kinetics.
  • HEPES (25–50 mM, pH 7.2–7.6): Zwitterionic, compatible with many proteins; no primary amines.
  • Carbonate/bicarbonate (50–100 mM, pH 8.3–8.5): Faster coupling but shorter NHS half-life; use when rapid labeling is feasible.

Recipe hints (general):

• Include 0–10% v/v dry DMSO or DMF to help solubilize hydrophobic payloads while keeping proteins stable.
• Degas and filter (0.22 µm) buffers to minimize oxidation/particulates for sensitive bioconjugations.
• For subsequent activation of the terminal –COOH with EDC/NHS, mildly acidic buffers like MES (pH ~5.5–6.0) are standard to stabilize the O-acylisourea intermediate.

Green Alternatives

Greener practice with NHS PEG COOH focuses on solvent choice, process intensification, and waste minimization; the core reagent is already effective at ambient temperatures, reducing energy use.

• Prefer greener solvents where compatible

  • Water/buffer for brief coupling steps at pH 6.0–7.4 can be used if reactions are rapid and concentrations are high to outcompete hydrolysis (tradeoff: stability).
  • 2-MeTHF or CPME may replace DCM/THF in some organic couplings (verify solubility of the specific PEG length).
  • Cyrene or propylene carbonate are emerging replacements for DMF/DMSO in select cases; assess stability of NHS ester and workup practicality.

• Process considerations

  • Use high-concentration stocks to reduce solvent volume.
  • Conduct reactions at room temperature to avoid unnecessary heating and NHS degradation.
  • Single-use aliquots decrease waste from degraded solutions.

• Comparison snapshot (general guidance)

  • DMF: Excellent solvent; reproductive toxicity profile and disposal concerns.
  • DMSO: Broadly usable; high viscosity and odor; safer profile than DMF but still requires care.
  • 2-MeTHF/CPME: Renewable/safer profile; lower polarity may limit PEG solubility.
  • Aqueous buffers: Greenest medium, but NHS half-life short; demands rapid kinetics and careful pH control.

Adopt solvent swaps only after small-scale solubility/stability screens for the particular PEG molecular weight and target.

Pharmaceutical Uses

No therapeutic claims are made. NHS PEG COOH is a research-grade linker for process development and analytical workflows.

General/formulation context (literature):

• Excipient/linker role: Heterobifunctional PEGs are used in R&D to prototype conjugates (e.g., ligand-to-protein, small-molecule-to-surface) and to tune hydrophilicity and spacing. The PEG segment can reduce aggregation and improve solubility of constructs in formulation screens.
• Preclinical process development: Enables structure–activity exploration of linker length and density in conjugate candidates, nanoparticles, and diagnostic reagents.
• Quality considerations: For regulated applications, specialized GMP or multi-compendial grades may be required; for this catalog item, grade is Not specified for this item; refer to CoA/Spec Sheet.
• Compatibility: Avoid amine-containing formulation buffers during the coupling step; after quenching/cleanup, final formulations can be prepared in standard pharmaceutically acceptable buffers as appropriate for the conjugate.

This product is supplied "For research use only" and is not intended for human or animal therapeutic use.

Physical Properties

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

General/literature characteristics for NHS-terminated PEGs (for context; not item specifications):

• Physical state: Typically solid (powder/wax) at room temperature for moderate Mn; highly hygroscopic and moisture-sensitive due to NHS ester.
• Solubility profile: Good solubility in polar aprotic solvents (DMF, DMSO, acetonitrile); variable solubility in water depending on PEG length and end-group ionization state; often soluble in dichloromethane and THF (literature).
• Acid/base behavior: The carboxyl terminus has a pKa typically ~4–5 when deprotected (literature); NHS ester is prone to hydrolysis in aqueous media, especially at pH > 7.5.
• Stability notes: NHS esters hydrolyze to the corresponding carboxylate and NHS in the presence of moisture; rate increases with pH, temperature, and water content (literature). Protect from light and store under inert gas as provided.

Always consult the CoA/Spec Sheet for item-specific values and the SDS for safety-related physical data.

Quality and Grades

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

Professional guidance on interpreting PEG linker quality (general):

• Polymer dispersity: PEG-based reagents are often specified by a nominal molecular weight with a polydispersity index (Đ). Lower Đ indicates narrower distribution, beneficial for reproducibility in conjugation and materials assembly (literature).
• Functional group content: For NHS PEG COOH, two key metrics are the substitution level (mmol functional group per gram) and residual free PEG/impurities. High functional group conversion improves coupling efficiency.
• Stabilizers/additives: Not specified for this item; refer to CoA/Spec Sheet. In general, NHS esters are supplied without basic stabilizers to avoid premature reaction; rigorous drying and inert packaging are typical.
• Analytical controls (typical for PEG linkers; not item-specific): NMR (1H, 13C) to verify end-group integration, FTIR for carbonyl signatures (anhydride/ester/acid), MALDI-TOF or GPC for Mn and Đ, and titration or HPLC to quantify active ester content.
• Application relevance: Higher purity and well-defined end-group content correlate with higher bioconjugation yields and lower background labeling. When selecting a lot, match Mn and end-group specifications to your protocol, and consult the CoA for exact values.

Reaction and Applications

NHS PEG COOH is a heterobifunctional crosslinker for modular assembly of amide-linked conjugates while retaining a free carboxyl for downstream chemistry.

Key application areas (literature/general):

• Bioconjugation to primary amines: NHS ester reacts with lysine residues, N-termini, or surface amines to form stable amide bonds under mild, near-neutral conditions.
• Surface and material functionalization: Introduce PEG spacing between surfaces (NPs, polymers, oxides with preinstalled amines) and a terminal carboxyl for further anchoring or ligand attachment (e.g., EDC coupling to peptides).
• Two-stage orthogonal assembly: First install via NHS–amine coupling; subsequently activate the remaining –COOH (e.g., EDC/NHS or DIC/HOBt) to attach amines or hydrazides, enabling sequential construction of heteroconjugates.
• Solubility tuning: The PEG spacer improves aqueous compatibility and reduces nonspecific adsorption (“stealth” effect), valuable in assay development and sensor fabrication.

Practical tips:

• Minimize water exposure and time in aqueous buffers; keep pH 6.0–7.4 during NHS coupling, then adjust for carboxyl activation as needed.
• Use freshly prepared solutions in dry DMF/DMSO; consider single-use aliquots.
• For proteins, degas buffers and avoid amine-containing buffers (e.g., Tris) that quench NHS esters. Prefer phosphate, HEPES, or MES depending on pH needs.
• Quench unreacted NHS groups with ethanolamine or glycine after coupling to suppress background reactivity.
• Verify coupling by appropriate analytics: UV–Vis (if chromophores present), SDS-PAGE shift, LC–MS, or surface assay (XPS/ATR-FTIR).

Reaction Conditions

Typical conditions for NHS–amine coupling and subsequent –COOH activation (general literature guidance; adapt to substrate and scale):

• NHS–amine coupling (organic medium)

  • Solvent: Dry DMF, DMSO, DCM, or NMP.
  • Base: DIPEA (1–3 equiv vs. amine) or TEA to neutralize the HCl salt of the amine and promote acylation.
  • Temperature: 20–25°C (often sufficient); 0–5°C for sensitive substrates; avoid heating which accelerates NHS hydrolysis.
  • Time: 0.5–4 h depending on nucleophile and concentration.
  • Concentration: 5–100 mM in linker; higher concentration increases rate but may impact selectivity.

• NHS–amine coupling (aqueous/mixed)

  • Buffer: MES (pH 6.0–6.5) or phosphate/HEPES (pH 7.0–7.4).
  • Organic cosolvent: 0–10% v/v dry DMF or DMSO as needed.
  • Stoichiometry: 2–10 equiv of NHS PEG COOH relative to amine sites on biomolecule for moderate labeling.
  • Time: 15–120 min at 20–25°C; monitor to avoid over-modification.

• Activation/coupling of the carboxyl terminus

  • Aqueous: EDC (1–2 equiv) with NHS (1–2 equiv) in MES buffer (pH 5.0–6.0), then add amine nucleophile at pH 7–8.
  • Organic: DIC (1–1.5 equiv) with HOBt/HOAt or Oxyma in dry DMF/DCM; add amine and base (DIPEA).

• Workup/purification

  • For small molecules: Aqueous quench, liquid–liquid extraction, and silica or reverse-phase chromatography (PEG often requires RP or precipitation).
  • For bioconjugates: Desalting columns, dialysis, or spin filters (MWCO matched to construct).

Note: Expected yields and kinetics vary with PEG length and substrate; perform pilot reactions to optimize.

Safety and Handling

• GHS classification, signal word, pictograms, H-statements: Not specified for this item; refer to SDS.

General handling guidance (professional/literature-based; defer to SDS for authoritative information):

• Primary hazards: Irritation to skin/eyes/respiratory tract is possible with NHS esters and PEG reagents. NHS esters are reactive acylating agents; avoid contact with skin, eyes, and mucous membranes.
• Moisture sensitivity: The NHS ester hydrolyzes upon exposure to moisture, reducing coupling efficiency. Work quickly on the bench with minimal ambient humidity.
• PPE: Wear lab coat, safety glasses or goggles, and appropriate chemically resistant gloves (e.g., nitrile). Use a certified chemical fume hood to avoid dust or vapor exposure and to handle anhydrous solvents.
• Incompatibilities: Avoid strong bases in aqueous solution (accelerates NHS hydrolysis), strong nucleophiles (amines, hydrazines) unless intended for coupling, and prolonged exposure to water or alcohols. Avoid oxidizers that may degrade organic components.
• First aid (overview): In case of skin/eye contact, rinse with copious water for at least 15 minutes; remove contaminated clothing. If inhaled, move to fresh air. If ingested, rinse mouth; seek medical attention in all cases.
• Spill response: Avoid dust generation. Collect solid carefully, wipe with damp disposable towels, and wash area with mild detergent. Dispose according to local regulations.
• Fire safety: Combustible organic solid. Use CO2, dry chemical, or foam. Thermal decomposition may produce carbon oxides and nitrogen oxides.
• Storage: As specified for this item—protected from light, under argon, at −20°C; keep tightly closed with desiccant.

Solvent Selection

NHS PEG COOH is best handled in dry, polar aprotic solvents that solubilize PEG and preserve the NHS ester.

• Recommended anhydrous solvents (literature guidance)

  • DMF or DMSO (anhydrous): Excellent solubility; ideal for stock solutions and amine coupling on biomolecules or surfaces.
  • Acetonitrile: Often suitable; lower viscosity than DMSO; confirm solubility versus PEG length.
  • Dichloromethane or THF: Useful for small-molecule synthesis; ensure low water content.
  • Water/buffer: Use sparingly and briefly; NHS ester hydrolyzes—keep pH ≤ 7.4 and minimize exposure time.

• Miscibility and polarity (general)

  • PEG moieties confer hydrophilicity; however, the NHS ester prefers low-water, neutral to slightly basic conditions for stability.
  • In aqueous systems, pair with buffering at pH 6.0–7.4 and rapid addition to amine-containing targets to outcompete hydrolysis.

• Choosing among solvents

  • For bioconjugation to proteins: Prepare a concentrated stock in dry DMSO or DMF and add dropwise to the aqueous protein solution; keep final organic ≤10% v/v to maintain protein integrity.
  • For small-molecule/solid-phase coupling: Use dry DMF, DCM, or NMP with a non-nucleophilic base (DIPEA) and molecular sieves if needed.

• Comparison (general)

  • DMF vs DMSO: DMF offers lower viscosity and easier removal; DMSO offers broader solubility. Both require rigorous drying.
  • Aqueous buffers provide biocompatibility but at the cost of faster NHS hydrolysis; use immediately after dissolution.

Storage and Reconstitution

• Storage conditions (item-specific): Protected from light, Store at −20°C, Argon charged. Shipped in an ice chest with ice pads. Maintain under inert atmosphere and keep container tightly closed with desiccant upon receipt.

• Reconstitution (general guidance):

  • Bring vial to room temperature under inert gas before opening to prevent moisture condensation.
  • Dissolve immediately before use in dry, oxygen-free solvent (e.g., anhydrous DMF or DMSO). Filter through a dry PTFE syringe filter if particulates are present.
  • Prepare concentrated stock solutions (e.g., 50–200 mM) and dispense into small, dry, inert-gas–flushed aliquots.

• Aliquoting and stability (general):

  • Store aliquots at −20°C under argon or nitrogen, protected from light. Avoid repeated freeze–thaw cycles.
  • Aqueous solutions are not recommended for storage due to NHS hydrolysis; prepare fresh immediately prior to use.
  • Monitor for loss of activity by test coupling or analytical methods if stored for extended periods.

• Incompatibilities: Avoid moisture, prolonged exposure to elevated temperatures, amine-containing buffers during storage, and strong bases which accelerate hydrolysis.

• Disposal: Dispose of solutions and residues according to institutional and local regulations for organic reagents and reactive esters.

Structure and Identity

NHS PEG COOH is a heterobifunctional polyethylene glycol (PEG) linker bearing an N-hydroxysuccinimide (NHS) ester at one terminus and a free carboxylic acid at the other. It is designed for selective amine coupling (via NHS) while leaving a terminal carboxyl for subsequent derivatization or immobilization.

• Item-specific identifiers

  • 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.
  • CAS: Not specified for this item; refer to CoA/Spec Sheet.
  • CID: Not specified for this item; refer to CoA/Spec Sheet.

• Structural features (general/literature description)

  • Polymer backbone: Repeat ethylene oxide units [–CH2–CH2–O–]n impart high hydrophilicity and flexibility.
  • Functional end-groups: One terminus is an activated carboxyl derivative as an NHS ester (succinimidyl), the opposite terminus is a free –COOH.
  • Functional group chemistry: NHS esters are acyl-activating groups that form amide bonds with primary amines under mild conditions; the free carboxyl can be further activated (e.g., EDC/NHS) for coupling to amines or converted to other derivatives (acid chloride, esters).
  • Typical presentation: Unless a discrete Mn is specified, PEG products exhibit a distribution (polydispersity) around the nominal chain length (literature).

Synthetic Utility

As a heterobifunctional linker, NHS PEG COOH enables orthogonal assembly strategies in organic and polymer synthesis.

Key reactivity elements (general):

• NHS ester terminus:
  • Forms amide bonds with primary amines under mild conditions in organic or mixed aqueous media.
  • Compatible with bases such as DIPEA/TEA in anhydrous solvents; in water, buffers at pH 7–8 favor coupling.
• Carboxylic acid terminus:
  • Activatable with EDC/NHS (aqueous) or DIC/HOBt/HOAt (organic) to form amide bonds to amines.
  • Convertible to acid chlorides (e.g., oxalyl chloride) for subsequent coupling to alcohols/amines, if conditions tolerate PEG.

Applications:

• Spacer installation in small-molecule conjugates to mitigate steric hindrance and enhance solubility.
• Stepwise dual-functionalization: Sequentially couple NHS end, then activate and couple the –COOH end to introduce a second functionality.
• Solid-phase synthesis and resin modification: Introduce PEGylated carboxyl handles to resins or supports pre-functionalized with amines, enhancing swelling and accessibility.

Practical notes:

• Control stoichiometry and reaction time to limit over-labeling in biomolecules.
• Use dry conditions and rapid workups to preserve the NHS ester during multistep sequences.
• Characterize products by NMR, IR (amide I/II), MS (as feasible for PEG distributions), and, for surfaces, by contact angle, XPS, or colorimetric amine assays.

Target Specificity

Not applicable. This product is a chemical linker, not a biological targeting reagent or antibody. No antigen, epitope, clone, isotype, or species reactivity applies.