Description

n-(m-Peg4)-N'-(Peg4-Acid)-Cy5 is a heterobifunctional polyethylene glycol (PEG) linker featuring a maleimide group for thiol conjugation and a carboxylic acid for amine coupling, conjugated to the cyanine dye Cy5. This compound is engineered to enable the site-specific labeling of biomolecules, such as proteins and antibodies, for advanced fluorescence-based applications. It is a critical reagent for researchers and developers in the fields of bioconjugation, bioimaging, and diagnostic assay development, providing a stable, water-soluble bridge for creating bright, functionalized probes.

Application

• Bioconjugation Reagent: For the site-specific labeling of thiol-containing proteins, peptides, or antibodies with a fluorescent Cy5 dye via the maleimide group.
• Fluorescent Probe Synthesis: Used to create custom fluorescent probes for in vitro and in vivo imaging studies by conjugating the carboxylic acid to targeting molecules like peptides or oligonucleotides.
• Diagnostic Assay Development: Essential for developing high-sensitivity fluorescence immunoassays (FLISA), lateral flow tests, and other diagnostic platforms.
• Flow Cytometry & Microscopy: Enables the preparation of brightly labeled antibodies and other detection reagents for cell analysis and confocal microscopy.
• Drug Delivery & Biotherapeutics: Acts as a functional linker in the design of antibody-drug conjugates (ADCs) or PEGylated therapeutic agents, incorporating a traceable fluorescent marker.
• Biomolecular Interaction Studies: Facilitates Förster Resonance Energy Transfer (FRET) and other proximity-based assays by labeling interacting partners.

Basic Information

Product Name	n-(m-Peg4)-N'-(Peg4-Acid)-Cy5
CAS No.	2107273-32-3
Molecular Formula	Contact for details
Molecular Weight	Contact for details
Synonyms	Maleimide-PEG4-acid-Cy5; Cy5 maleimide PEG4 acid; mPEG4-Cy5-acid; Cy5-PEG4-MAL-COOH; N-(Maleimide-PEG4)-N'-(PEG4-acid)-Cy5 dye; Heterobifunctional PEG-Cy5 linker; Cy5-PEG4(4)-Maleimide-PEG4(4)-Acid; Fluorescent PEG crosslinker
EINECS	Contact for details

Quality Control

Every batch of n-(m-Peg4)-N'-(Peg4-Acid)-Cy5 is manufactured and analyzed under strict quality protocols to ensure high purity and consistent performance for sensitive research applications. Our products undergo rigorous quality testing, including HPLC for purity and identity confirmation, to ensure compliance with industry standards. Certificates of Analysis (COA) with detailed chromatographic data are available upon request.

Storage

Preserve in a tightly closed container, protected from light. Store desiccated at -20°C or below. This compound is strictly light-sensitive (protect from all light exposure) and hygroscopic (moisture-sensitive). Allow the vial to equilibrate to room temperature in a desiccator before opening to minimize moisture uptake.

Specification

Item	Specification
Appearance	Dark blue to purple solid or film
Identification (HPLC)	Conforms to reference standard
Purity (HPLC)	≥ 95%
Extinction Coefficient	~250,000 M⁻¹cm⁻¹ (at λmax ~649 nm)
Solubility	Soluble in DMSO, DMF, water (after conjugation)

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.