Protein Modification Reagents

Medchemexpress LLC Propanoic acid, 3-[[13-(4-formylphenyl)-13-oxo-3,6,9-trioxa-12-azatridec-1-yl]oxy]- | 1309460-27-2 | MFCD18916985 | 99.1% | 397.42 g/mol | C19H27NO8 | 100 MG

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Ald-Ph-amido-PEG4-C2-acid is a non-cleavable PEG4-based linker designed for use in antibody-drug conjugate (ADC) research. Supplied as a powder for conjugation experiments and linker development.

• Non-cleavable PEG4 linker for stable antibody-payload conjugation.
• Aldehyde functional group suitable for oxime or hydrazone conjugation chemistry.
• Purity 99.1% (LCMS).
• Molecular weight 397.42 g/mol and formula C19H27NO8.
• Soluble to 10 mM in DMSO.
• Store as a powder at -4°C under nitrogen.
• Available as 100 MG powder for research applications.

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Medchemexpress LLC 3,6,9,12-tetraoxapentadec-14-yn-1-ol, 1-(4-methylbenzenesulfonate) | 875770-32-4 | 99.3% | 386.46 | C18H26O7S | 1 G

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Propargyl-PEG4-Tos is a PEG-based linker bearing a propargyl (alkyne) terminus and a tosylate leaving group used in synthesis workflows for PROTACs, ADCs, and click-chemistry conjugation.

• Enables copper-catalyzed azide-alkyne cycloaddition for bioconjugation.
• Suitable as a cleavable linker for antibody-drug conjugate synthesis.
• Applicable for PROTAC linker assembly and modular synthesis.
• High reported purity (99.25%), supporting reliable synthetic performance.
• Molecular weight 386.46 and formula C18H26O7S.

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Medchemexpress LLC Dbco-PEG3-TCO | 2755573-20-5 | 98.0% | 631.76 g·mol⁻¹ | C36H45N3O7 | 50 MG

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DBCO-PEG3-TCO is a heterobifunctional click-chemistry linker used for bioconjugation and antibody-drug conjugate (ADC) synthesis. It contains a dibenzocyclooctyne (DBCO) group for strain-promoted alkyne-azide cycloaddition and a trans-cyclooctene (TCO) group for rapid tetrazine ligation, joined by a three-unit polyethylene glycol (PEG3) spacer, enabling aqueous-phase conjugation and improved solubility.

• Facilitates catalyst-free azide-alkyne cycloaddition and tetrazine ligation
• Heterobifunctional design enables orthogonal dual conjugation strategies
• PEG3 spacer improves solubility and reduces steric hindrance
• High purity suitable for bioconjugation workflows
• Available in small milligram pack sizes for research use

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Medchemexpress LLC N3-PEG4-C2-NHS ester | 944251-24-5 | MFCD13184948 | 98.9% | 388.37 | C15H24N4O8 | 25 MG

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N3-PEG4-C2-NHS ester is a non-cleavable 4-unit polyethylene glycol (PEG) linker containing an azide group and an N-hydroxysuccinimide (NHS) ester for amine coupling; it is used for bioconjugation and click chemistry applications such as antibody-drug conjugate synthesis.

• Azide functional group enables copper-catalyzed azide-alkyne cycloaddition (CuAAC) and strain-promoted alkyne-azide cycloaddition (SPAAC).
• NHS ester reacts with primary amines to form stable amide bonds for labeling.
• Four-unit PEG spacer increases solubility and reduces steric hindrance.
• High purity suitable for research-grade bioconjugation workflows.
• Stable when stored under recommended low-temperature conditions to preserve reactivity.

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Cayman Chemical ANTIBODY DBCO acId 100mg

A copper-free click chemistry reagent; has been used in the study of glycoprotein charge effects on the migration and invasion of 9-azido sialic acid-labeled cancer cells in vitro; has also been used in the synthesis of DBCO-modified RNase A to deliver RNase A into AAM-labeled cancer cells in vitro and in vivo to induce cytotoxicity and reduce tumor growth, respectively

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Broadpharm N-Mal-N-bis(PEG2-NHS ester) | 2182601-73-4 | MFCD29912828 | 50mg

N-Mal-N-bis(PEG2-NHS ester) | Purity: 98% | MW: 682.632 | 2182601-73-4 | MFCD29912828 | 50mg

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Medchemexpress LLC Gly-gly-gly-PEG4-azide | 3070260-22-6 | 99.8% | 433.46 | C16H31N7O7 | 10 MG

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Gly-Gly-Gly-PEG4-azide is a cleavable azide-functional linker used in antibody-drug conjugate (ADC) synthesis and bioconjugation. It provides an azide handle for copper-catalyzed azide-alkyne cycloaddition (CuAAC) and strain-promoted alkyne-azide cycloaddition (SPAAC), enabling bioorthogonal conjugation of payloads to antibodies and other biomolecules.

• Contains an azide functional group for bioorthogonal click reactions.
• Cleavable linker compatible with ADC synthesis workflows.
• High purity suitable for research applications.
• Oil appearance with defined solvent storage stability under nitrogen.
• Available in small-scale milligram pack sizes for research use.

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Medchemexpress LLC DBCO-PEG2-NHS ester | 2585653-12-7 | MFCD34551891 | ≥98.0% | 561.58 | C30H31N3O8 | 10 MG

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DBCO-PEG2-NHS ester is an amine-reactive, click-chemistry reagent that installs a dibenzocyclooctyne (DBCO) handle via an N-hydroxysuccinimide (NHS) ester and a short PEG2 spacer. It is designed for efficient bioconjugation and copper-free strain-promoted azide-alkyne cycloaddition in research applications.

• Amine-reactive NHS ester enables rapid and selective coupling to primary amines.
• DBCO functionality supports copper-free strain-promoted click chemistry.
• P EG2 spacer improves solubility and reduces steric hindrance for conjugation.
• High purity (≥98.0%) suitable for sensitive research workflows.
• Stable as powder at -20°C for long-term storage.

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eMolecules​ Broadpharm / DBCO-PEG6-NHS ester / 25mg / 698442844 / BP-25725 / / / [null] / 737.803 / C38H47N3O12

Broadpharm / DBCO-PEG6-NHS ester / 25mg / 698442844 / BP-25725 / / / [null] / 737.803 / C38H47N3O12

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Medchemexpress LLC DSPE PEG thiol | 25322-68-3 | 99.4% | 2000 (average) | 100 MG

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DSPE-PEG-SH (MW 2000) is a thiol-terminated pegylated phospholipid used to introduce reactive thiol groups into lipid assemblies. The thiol group readily forms stable thioether linkages with maleimide and other electrophiles, enabling surface functionalization of liposomes and lipid nanoparticles for targeted delivery and conjugation of ligands such as peptides or antibodies.

• Thiol terminus enables covalent conjugation with maleimide groups.
• Incorporates into liposomes and lipid nanoparticles for surface functionalization.
• Amphipathic structure supports bilayer formation in aqueous systems.
• High purity (≈99.4%) suitable for research applications.
• Soluble in water and DMSO with warming and sonication.

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Medchemexpress LLC m-PEG-DMG | 1019000-64-6 | 98.0% | 2000 Da (average) | (C2H4O)nC36H73NO5 | 100 MG

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m-PEG-DMG (MW 2000) is a methoxy-terminated polyethylene glycol conjugated to dimyristoylglycerol. Supplied as a solid with an average molecular weight of about 2000 Da, it is formulated for preparation of PEGylated liposomes and lipid nanoparticles used in drug delivery research and related in vitro studies.

• High purity (98.0%).
• Average molecular weight ~2000 Da.
• White to off-white solid form.
• Suitable for liposome and lipid nanoparticle formulation.
• Provides steric stabilization and reduced protein opsonization.
• Available in small laboratory pack sizes (e.g., 5-100 mg).
• Documentation available: data sheet, COA, and SDS.

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eMolecules​ Bromoacetamido-PEG3-acid | 1807534-79-7 | MFCD28950780 | 500mg

Broadpharm | Bromoacetamido-PEG3-acid | 500mg | 282987835 | BP-22762 | 98.000 | 1807534-79-7 | MFCD28950780 | 342.186 | C11H20BrNO6

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eMolecules​ Broadpharm / Methyltetrazine-PEG3-amine / 50mg / 649282308 / BP-26276 / 98.000 / 2141976-28-3 / [null] / 404.471 / C19H28N6O4

Broadpharm / Methyltetrazine-PEG3-amine / 50mg / 649282308 / BP-26276 / 98.000 / 2141976-28-3 / [null] / 404.471 / C19H28N6O4

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Medchemexpress LLC Biotin-PEG4-amino-t-Bu-DADPS-C3-alykne | 2241685-22-1 | 95.0% | C42H62N4O9SSi | 10MG

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Biotin-PEG4-amino-t-Bu-DADPS-C3-alykne is a PEG-based bioconjugation linker combining a biotin tag, a PEG4 spacer, a primary amino handle, a DADPS cleavable protecting group, and a terminal alkyne for copper-catalyzed azide-alkyne cycloaddition (CuAAC). It is designed for use in PROTAC assembly, affinity capture, and click-chemistry-based labeling workflows.

• Contains a terminal alkyne for CuAAC click chemistry.
• Includes a biotin moiety for affinity capture or detection.
• PEG4 spacer improves solubility and reduces steric hindrance.
• Primary amino handle enables amide coupling to carboxyl-containing partners.
• DADPS group provides acid-cleavable protection for controlled release.
• Stable as a powder when stored cold and protected from light.

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eMolecules​ Medchem Express / DBCO-S-S-PEG3-biotin / 5mg / 686240556 / HY-140128 / / 1430408-09-5 / MFCD22380733 / 869.120 / C42H56N6O8S3

Medchem Express / DBCO-S-S-PEG3-biotin / 5mg / 686240556 / HY-140128 / / 1430408-09-5 / MFCD22380733 / 869.120 / C42H56N6O8S3

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