DusQ 21 NHS ester | CAS 304014-13-9

DusQ 21 NHS ester is an NHS-ester activated quencher designed for rapid, covalent conjugation to primary amines on proteins, peptides, and amine-functionalized biomaterials. In fluorescence workflows, it is used to suppress donor emission in labeled conjugates and to tune background in fluorescence-based assays where quencher-fluorophore proximity is controlled by the labeling chemistry and conjugate architecture.

1. Protein Conjugate Quenching

DusQ 21 NHS ester is used by protein chemistry and chemical biology groups to generate quenched protein conjugates for fluorescence imaging and assay development. By reacting with lysine residues or N-terminal amines, it enables researchers to introduce quencher functionality directly onto antibodies, enzymes, or affinity reagents, supporting signal control in donor-quencher constructs used for labeling verification, background reduction, and fluorescence readouts that depend on quencher placement within a defined conjugate.

2. FRET Pair Signal Control

DusQ 21 NHS ester is commonly incorporated into FRET-based assay systems where quenching of a fluorescent donor is required to establish a low baseline prior to a fluorescence change event. Researchers use the NHS-ester chemistry to attach DusQ 21 to proteins, peptides, or polymer scaffolds that serve as FRET donors or acceptor partners, enabling distance-dependent signal modulation in solution assays and plate-based fluorescence formats during probe optimization and assay prototyping.

3. Amine-Functional Surface Modification

DusQ 21 NHS ester supports biomaterials and surface engineering workflows that require immobilized quenching capacity, such as quencher-functional coatings for fluorescence background management. Materials scientists and assay developers conjugate the NHS ester to amine-bearing surfaces (e.g., amine-terminated polymers, porous substrates, or biosensor interfaces) to create quencher-dense regions that reduce unwanted fluorescence from labeled components used in microscopy, imaging assays, or immobilized binding formats.

4. Fluorescent Oligonucleotide Labeling Control

DusQ 21 NHS ester is used to prepare quencher-modified oligonucleotide reagents when amine-containing oligonucleotide handles or linkers are present. In nucleic-acid assay development, researchers conjugate the quencher to amine-functional oligos to manage fluorescence output from labeled probes, supporting probe design studies where quencher positioning is adjusted by linker chemistry to achieve robust signal behavior in fluorescence-based nucleic acid readouts.