Protein Modification Reagents
AURORA BIOLABS LLC TR-FRET Cereblon-4C Binding Assay Kit,384 rxn
E3 ubiquitin ligases are enzymes that catalyze the final step of the ubiquitination process and play essential roles in targeted protein degradation. Cereblon (CRBN) is the substrate-recognition component of the CRBN/DDB1/CUL4A/RBX1 E3 ubiquitin ligase complex and is widely used in PROTAC (Proteolysis-Targeting Chimera) drug discovery for targeted protein degradation applications. The TR-FRET Cereblon-4C Binding Assay Kit is designed to quantitatively measure the binding interaction between CRBN and its ligands. The assay includes Tag1-CRBN-4C complex, terbium-labeled anti-Tag1 antibody, and fluorescently labeled thalidomide ligand. Binding of CRBN to thalidomide generates a fluorescence resonance energy transfer (FRET) signal detected by measuring fluorescence emission at 665 nm and 620 nm. Compounds that compete with thalidomide for CRBN binding reduce the HTRF signal, enabling evaluation of CRBN-targeting molecules for drug discovery and PROTAC research applications.
Medchemexpress LLC Bromoacetamido-PEG5-DOTA | 2353410-19-0 | 98.0% | C30H55BrN6O13 | 50 MG
Bromoacetamido-PEG5-DOTA is a PEG-based PROTAC linker utilized in the synthesis of PROTACs. These compounds employ two distinct ligands connected by a linker, one targeting an E3 ubiquitin ligase and the other a target protein. PROTACs leverage the intracellular ubiquitin-proteasome system for selective degradation of target proteins. This product appears as a white to off-white oil.
- PEG-based PROTAC linker
- Used in the synthesis of PROTACs
- Appears as a white to off-white oil
- For research use only
Medchemexpress LLC Azide-PEG-amine (MW 2000) | 95.0% | 100 MG
Azide-PEG-amine (MW 2000) is a PEG-based PROTAC linker used in the synthesis of PROTACs. It functions as a click chemistry reagent.
- Contains an azide group.
- Participates in copper-catalyzed azide-alkyne cycloaddition (CuAAc) reactions with alkyne-containing molecules.
- Undergoes strain-promoted alkyne-azide cycloaddition (SPAAC) reactions with molecules containing DBCO or BCN groups.
Medchemexpress LLC Mal-PEG2-Val-Cit-PABA-PNP | 1345681-52-8 | 96.8% | 755.73 | C34H41N7O13 | 5 MG
Mal-PEG2-Val-Cit-PABA-PNP is a cleavable linker used in the synthesis of antibody-drug conjugates (ADCs). It contains a maleimide reactive group, a two-unit polyethylene glycol spacer, and a protease-sensitive Val-Cit-PABA peptide spacer that enables payload release in target cells.
- cleavable linker for ADC synthesis
- contains maleimide (Mal) reactive group
- two-unit PEG spacer (PEG2) provides solubility and flexibility
- val-cit-paba sequence is protease sensitive for intracellular release
- para-nitrophenyl (PNP) activating group for conjugation chemistry
- solid, white to off-white appearance; high purity
- available in multiple sizes and requires protection from light and storage under inert gas
Medchemexpress LLC Dspe-peg-biotin | 98.4% | 3400 Da | 25 MG
Biotinylated DSPE-PEG is an amphiphilic PEG-lipid conjugate (average molecular weight 3,400 Da) used to introduce biotin functionality into lipid assemblies. The DSPE lipid anchors the conjugate in bilayers while the PEG spacer presents biotin for high-affinity interactions with streptavidin/avidin. Supplied as a powder for research use, it is commonly applied in targeted delivery, surface functionalization, and assay development.
- Amphiphilic structure enables incorporation into liposomes and micelles.
- Biotin end-group for high-affinity binding to streptavidin/avidin.
- Average molecular weight 3.4 kDa for the PEG spacer.
- High reported purity (~98.4%).
- Available in small powder pack sizes for research use (for example, 25 mg).
- Recommended storage as powder at -20°C to maintain stability.
Medchemexpress LLC NHS-PEG1-SS-PEG1-NHS | 1688598-83-5 | 98.0% | 436.41 | 50 MG
NHS-PEG1-SS-PEG1-NHS is a reversible linker designed for conjugating biomacromolecules with active small molecules.
- Reversible linker
- Designed for conjugating biomacromolecules with active small molecules
- Suitable for use in proteins
- Suitable for use in liposomes
- Suitable for use in nanoparticles
Medchemexpress LLC Mal-PEG2-NHS ester | 1433997-01-3 | MFCD24539465 | 98.6% | 354.31 | C15H18N2O8 | 100 MG
Mal-PEG2-NHS ester is a bifunctional PEG linker designed for bioconjugation, combining a maleimide moiety for thiol coupling with an NHS ester for amine coupling to enable antibody-drug conjugate (ADC) and other conjugation chemistries.
- Non-cleavable dual-reactive linker enabling site-specific conjugation.
- Two-unit PEG spacer increases hydrophilicity and solubility.
- Maleimide group reacts selectively with thiol groups.
- NHS ester reacts with primary amines for stable amide bond formation.
- Available in small-scale quantities suitable for research use.
- Stored and handled to preserve stability: long-term frozen storage recommended.
![eMolecules bis-PEG2-endo-BCN | Broadpharm | 1476737-97-9 | MFCD19705423 | 500.636 | C28H40N2O6 | 97.000 | O=C(NCCOCCOCCNC(=O)OC[C@@H]1[C@@H]2CCC#CCC[C@H]12)OC[C@@H]1[C@@H]2CCC#CCC[C@H]12 | 50mg | 340377180](https://assets.fishersci.com/TFS-Assets/CCG/product-images/NC1737768.jpg-250.jpg)
eMolecules bis-PEG2-endo-BCN | Broadpharm | 1476737-97-9 | MFCD19705423 | 500.636 | C28H40N2O6 | 97.000 | O=C(NCCOCCOCCNC(=O)OC[C@@H]1[C@@H]2CCC#CCC[C@H]12)OC[C@@H]1[C@@H]2CCC#CCC[C@H]12 | 50mg | 340377180
bis-PEG2-endo-BCN | Broadpharm | 1476737-97-9 | MFCD19705423 | 500.636 | C28H40N2O6 | 97.000 | O=C(NCCOCCOCCNC(=O)OC[C@@H]1[C@@H]2CCC#CCC[C@H]12)OC[C@@H]1[C@@H]2CCC#CCC[C@H]12 | 50mg | 340377180
Medchemexpress LLC Aminooxy-PEG1-azide | 2100306-70-3 | MFCD30723212 | 98.0% | 146.15 g/mol | C4H10N4O2 | 5 MG
Aminooxy-PEG1-azide is a short bifunctional polyethylene glycol (PEG) linker bearing an aminooxy group and an azide group. It is designed for chemical biology and bioconjugation applications where orthogonal conjugation is required, enabling oxime ligation at one terminus and click chemistry at the other. Intended for research use only.
- Enables oxime ligation with aldehydes and ketones.
- Participates in copper-catalyzed and strain-promoted azide-alkyne cycloadditions.
- Provides a short PEG spacer to improve aqueous solubility and reduce steric hindrance.
- Suitable for linker construction in proteolysis targeting chimeric molecule (PROTAC) and bioconjugation workflows.
- Reported purity approximately 98%, compatible with research applications.
Medchemexpress LLC DOTA-PEG5-amine | 98.0% | 666.76 | 50 MG
DOTA-PEG5-amine is a PEG-based PROTAC linker designed for the synthesis of PROTACs. These molecules feature two ligands connected by a linker, one targeting an E3 ubiquitin ligase and the other a target protein. PROTACs utilize the intracellular ubiquitin-proteasome system to selectively degrade specific target proteins.
- PEG-based PROTAC linker
- Used in the synthesis of PROTACs
- Contains two different ligands connected by a linker
- Exploits the intracellular ubiquitin-proteasome system
- Selectively degrades target proteins
- For research use only
eMolecules 16-(Amine-PEG4-ethylcarbamoyl)pentadecanoic-t-butyl ester | Broadpharm |560.817 | C30H60N2O7 | 95.000 | CC(C)(C)OC(=O)CCCCCCCCCCCCCCC(=O)NCCOCCOCCOCCOCCN | 100mg | 795361477
16-(Amine-PEG4-ethylcarbamoyl)pentadecanoic-t-butyl ester | Broadpharm |560.817 | C30H60N2O7 | 95.000 | CC(C)(C)OC(=O)CCCCCCCCCCCCCCC(=O)NCCOCCOCCOCCOCCN | 100mg | 795361477
eMolecules 2055042-60-7 | N-(Boc-PEG3)-N-bis(PEG2-alcohol) | Broadpharm | MFCD30182039 | 556.694 | C25H52N2O11 | 97.000 | CC(C)(C)OC(=O)NCCOCCOCCOCCN(CCOCCOCCO)CCOCCOCCO | 500mg | 309208953
N-(Boc-PEG3)-N-bis(PEG2-alcohol) | Broadpharm | 2055042-60-7 | MFCD30182039 | 556.694 | C25H52N2O11 | 97.000 | CC(C)(C)OC(=O)NCCOCCOCCOCCN(CCOCCOCCO)CCOCCOCCO | 500mg | 309208953