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CAS 6066-82-6 Bioconjugation Reagent Bioconjugation Reagent High Purity GMP Grade

N-Hydroxysuccinimide (NHS)

IUPAC: 1-Hydroxypyrrolidine-2,5-dione View on PubChem
CAS NUMBER
6066-82-6
MOL. FORMULA
C4H5NO3
MOL. WEIGHT
115.09 g/mol
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Scientific Overview

NHS functions as a leaving group activator: when coupled to a carboxylic acid (commonly via carbodiimide chemistry using EDC or DCC), it forms an NHS ester that is far more reactive toward nucleophilic amines than the parent acid, while remaining stable enough for isolation and storage. This mild, selective reactivity underlies its central role in bioconjugation chemistry, including antibody-drug conjugate synthesis, PEGylation, and surface functionalization.

N-Hydroxysuccinimide (NHS) is a cyclic imide widely used as a coupling reagent in peptide synthesis, bioconjugation, and polymer chemistry. It is best known for forming NHS-activated esters that react selectively with primary amines to generate stable amide bonds.

Full Technical Data
Chemical Name N-Hydroxysuccinimide (NHS, HOSu)
CAS Number 6066-82-6
IUPAC Name 1-Hydroxypyrrolidine-2,5-dione
Molecular Formula C4H5NO3
Molecular Weight 115.09 g/mol g/mol
Reaction Scheme
Succinic Anhydride
Hydroxylamine (or Hydroxylamine Hydrochloride)
NA
N-Hydroxysuccinimide
NA
Commercial Applications

Bioconjugation Chemistry

Core reagent for forming NHS-ester--activated proteins, peptides, and antibodies used in ADC and labeling chemistry.

Peptide Synthesis

Used to generate active esters that facilitate amide bond formation under mild conditions.

PEGylation

Key activator for coupling PEG polymers to therapeutic proteins to extend circulation half-life.

Diagnostic & Surface Chemistry

Applied in surface functionalization for biosensors, microarrays, and SPR-based diagnostic platforms.

Market Therapeutic Focus
BIOCONJUGATION REAGENT PHARMACEUTICAL MANUFACTURING BIOCONJUGATES & ADCS PEPTIDE THERAPEUTICS DIAGNOSTICS & BIOSENSORS CRO/CDMO
Scientific Literature

NHS Esters in Bioconjugate Chemistry

Authors: Hermanson, G.T.

Bioconjugate Techniques (reference text)

Active Ester Coupling Methods in Peptide Synthesis

Authors: Anderson, G.W. et al.

J. Am. Chem. Soc.

DOI: 10.1021/ja00901a052

Direct Ca-Heteroarylation Mediated by N-Hydroxysuccinimide

Authors: Liu, W. et al.

Org. Lett.

DOI: 10.1021/acs.orglett.7b02890
Peer Queries & FAQs
Why is NHS used to activate carboxylic acids?
It converts a carboxylic acid into a reactive ester that couples efficiently and selectively with primary amines, enabling mild, high-yield amide bond formation without racemization.
What reagents are typically paired with NHS?
Carbodiimides such as EDC (water-soluble) or DCC are commonly used together with NHS to activate carboxylic acids for coupling.
Is NHS stable in aqueous solution?
NHS esters hydrolyze over time in aqueous buffer, particularly at higher pH, so reactions are typically carried out promptly after ester formation.
What is the recommended storage condition?
Store in a tightly sealed, moisture-protected container at room temperature or 2--8°C to prevent hydrolytic degradation.

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