BHQ-3 NHS | CAS 871240-94-7

BHQ-3 NHS is an NHS-ester functionalized fluorescence quencher designed to be covalently incorporated into labeling workflows where fluorescence signal suppression is required. As a BHQ-series quencher, it is commonly used to control background in oligonucleotide and FRET-based assay formats by providing strong non-emissive quenching when positioned in close proximity to a compatible fluorophore. The NHS-ester reactivity enables straightforward conjugation to primary amines on biomolecules, peptides, and proteins, supporting construction of quencher-bearing probes and conjugates for fluorescence readouts.

1. FRET Pair Construction

BHQ-3 NHS is used to build FRET quencher-acceptor or quencher-donor systems in fluorescence assay development, where signal output depends on the distance between the fluorophore and the quencher. Researchers incorporate the NHS-ester into amine-containing biomolecules or labeling scaffolds to position the quencher for efficient suppression of donor emission in the "off" state. This approach is frequently applied in molecular sensing and molecular interaction studies, including probe designs where target binding or enzymatic processing changes fluorophore-quencher proximity and thereby modulates fluorescence intensity.

2. Oligonucleotide Probe Quenching

BHQ-3 NHS supports fluorescence-controlled nucleic acid assays by enabling quencher installation onto amine-modified oligonucleotides or nucleic-acid-binding constructs that present primary amines for NHS-ester coupling. In common molecular beacon and hybridization-style workflows, the quencher helps reduce background fluorescence from a reporter dye when the probe is in a non-productive conformation. By anchoring BHQ-3 to the nucleic-acid reagent, assay developers can create robust fluorescence switching behavior for nucleic-acid detection and real-time fluorescence monitoring in research and industrial assay development settings.

3. Protein and Peptide Labeling

BHQ-3 NHS is routinely used by chemical biology and biomolecular assay teams to generate quencher-labeled proteins, peptides, or antibody-derived reagents for fluorescence-based readouts. NHS-ester coupling to lysine residues or other accessible primary amines enables site-agnostic but practical quencher incorporation, allowing researchers to tailor quencher density on the conjugate to meet assay design needs. These quencher-bearing biomolecules are then used in fluorescence suppression experiments, including enzyme activity formats and binding assays where quencher placement is leveraged to control reporter emission and improve interpretability of fluorescence signals.

4. Molecular Beacon and Switch Probes

BHQ-3 NHS is applied in the construction of fluorescence switch probes where quencher-bearing components are engineered to regulate reporter intensity during conformational changes. Teams designing beacon-like architectures use the NHS-ester chemistry to attach the quencher to amine-functionalized probe backbones, enabling efficient suppression of fluorophore emission in the closed or unbound state. When the probe transitions to an open or target-associated conformation, fluorescence recovery provides a direct optical signal for monitoring nucleic-acid interactions and other binding-driven switching events in assay development workflows.