Biotin-PEG4-NHS ester | CAS 459426-22-3

Name: Biotin-PEG4-NHS ester
Brand: BOC Sciences
Rating: 5 (1 reviews)

Catalog Number	R01-0474
Category	NHS Esters
Molecular Formula	C25H40N4O10S
Molecular Weight	588.67

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Product Introduction

Biotin-PEG4-NHS ester is a heterobifunctional reagent that features a biotin moiety linked to an NHS ester through a polyethylene glycol (PEG) spacer. This compound is designed for efficient bioconjugation, enabling the covalent attachment of biotin to primary amines on proteins, peptides, or other biomolecules via the NHS ester group. The PEG4 spacer imparts increased solubility and flexibility, facilitating the biotinylation process in various labeling and surface modification applications, particularly in the context of affinity purification and detection assays.

Chemical Information
Product Specification
Application

Chemical Information

Synonyms	3-[2-[2-[2-[2-[[5-[(3aS,4S,6aR)-2-oxo-1,3,3a,4,6,6a-hexahydrothieno[3,4-d]imidazol-4-yl]-1-oxopentyl]amino]ethoxy]ethoxy]ethoxy]ethoxy]propanoic acid (2,5-dioxo-1-pyrrolidinyl) ester; (2,5-dioxopyrrolidin-1-yl) 3-[2-[2-[2-[2-[5-[(3aS,4S,6aR)-2-oxo-1,3,3a,4,6,6a-hexahydrothieno[3,4-d]imidazol-4-yl]pentanoylamino]ethoxy]ethoxy]ethoxy]ethoxy]propanoate
Purity	>97%
IUPAC Name	(2,5-dioxopyrrolidin-1-yl) 3-[2-[2-[2-[2-[5-[(3aS,4S,6aR)-2-oxo-1,3,3a,4,6,6a-hexahydrothieno[3,4-d]imidazol-4-yl]pentanoylamino]ethoxy]ethoxy]ethoxy]ethoxy]propanoate
SMILES	C1CC(=O)N(C1=O)OC(=O)CCOCCOCCOCCOCCNC(=O)CCCCC2C3C(CS2)NC(=O)N3
InChI	InChI=1S/C25H40N4O10S/c30-20(4-2-1-3-19-24-18(17-40-19)27-25(34)28-24)26-8-10-36-12-14-38-16-15-37-13-11-35-9-7-23(33)39-29-21(31)5-6-22(29)32/h18-19,24H,1-17H2,(H,26,30)(H2,27,28,34)/t18-,19-,24-/m0/s1
InChIKey	DTLVBHCSSNJCMJ-JXQFQVJHSA-N
Solubility	In DMSO: 125 mg/mL (212.34 mM; Need ultrasonic)
Density	1.3±0.1 g/cm3
Appearance	Solid powder
LogP	0.87850

Product Specification

Storage

-20°C, protect from light. The solution be prepared immediately before its experimental application.

Application

Biotin-PEG4-NHS ester is a bioconjugation reagent built on a biotin handle linked through a short polyethylene glycol (PEG4) spacer and capped with an N-hydroxysuccinimide (NHS) ester for amide coupling. As an NHS-activated ester, it is widely used for covalent attachment to primary amines on proteins, peptides, and other amine-functionalized biomaterials, enabling robust biotin labeling for downstream affinity-based workflows. The PEG spacer helps improve solubility and accessibility of the biotin tag, which is particularly valuable in molecular imaging, diagnostics development, and affinity purification of labeled targets.

1. Protein Biotinylation

Biotin-PEG4-NHS ester is commonly used to introduce biotin onto lysine-rich proteins and antibody fragments for research-grade labeling. Laboratories use the PEG spacer to maintain target solubility and to support efficient binding of the biotin moiety to streptavidin or avidin reagents in pull-down assays, Western blotting, and flow cytometry sample preparation. The NHS ester format makes it a practical choice for generating biotinylated biomolecules that can be immobilized on streptavidin-coated surfaces or captured on affinity matrices for purification and analytical workflows.

2. Antibody and Affinity Tagging

Biotin-PEG4-NHS ester is frequently selected for biotinylating antibodies, nanobodies, and other targeting ligands to enable modular assembly of detection and capture platforms. By installing a biotin handle onto amine groups, researchers can standardize conjugation strategies that rely on streptavidin/avidin scaffolds, including multiplex assay formats and surface-based binding studies. The PEG4 linker supports presentation of the biotin tag away from the protein surface, which helps reduce steric constraints when constructing immunoassay reagents, affinity capture tools, and labeled binding reagents for assay development.

3. Streptavidin Surface Immobilization

Biotin-PEG4-NHS ester is widely used to functionalize amine-containing materials and to create biotinylated probes for immobilization on streptavidin-coated plates, beads, and sensor surfaces. In biomaterials and molecular imaging workflows, this reagent enables consistent attachment of capture molecules or imaging handles to solid supports through the high-affinity biotin–streptavidin interaction. The PEG spacer improves accessibility of the immobilized biotin, supporting reproducible binding behavior in workflows such as surface binding assays, imaging probe staging, and affinity-based enrichment of labeled components.

4. Diagnostic and Assay Reagent Design

Biotin-PEG4-NHS ester is used in the development of diagnostic and analytical reagent components where biotin serves as a universal affinity tag for assembling complex assay architectures. Teams designing ELISA-like formats, lateral flow assay components, and bead-based detection workflows often biotinylate assay reagents to enable standardized coupling to streptavidin/avidin conjugates. The NHS ester chemistry supports straightforward labeling of amine-bearing assay proteins and reagents, while the PEG4 spacer helps preserve reagent performance in solution and on surfaces by maintaining biotin accessibility for downstream affinity steps.