Atto 425-NHS ester | CAS 892156-28-4

ATTO 425-NHS ester is a reactive ATTO 425 fluorophore formulated as an N-hydroxysuccinimide (NHS) ester for efficient covalent labeling of primary amines. This amine-reactive dye is widely used to generate fluorescent protein, peptide, and antibody conjugates for microscopy and fluorescence-based assays, where blue-to-cyan excitation and bright emission support sensitive visualization and quantification. In labeling workflows, the NHS ester chemistry enables straightforward conjugate preparation under standard bioconjugation conditions, making it a common reagent for building fluorescent standards and imaging reagents.

1. Protein And Antibody Labeling

ATTO 425-NHS ester is frequently used by protein engineering and chemical biology groups to prepare fluorescently labeled antibodies, enzymes, and purified protein conjugates for downstream imaging and binding assays. Because NHS esters react with accessible lysine residues and N-terminal amines, the reagent is commonly employed to generate labeled affinity reagents and detection conjugates for fluorescence microscopy, plate-based fluorescence readouts, and assay development. Researchers often choose ATTO 425-NHS ester when they need a compact, amine-reactive fluorophore that can be incorporated into biomolecules without introducing reactive handles that could complicate subsequent bioconjugation steps.

2. Fluorescence Microscopy Staining

ATTO 425-NHS ester is used to fluorescently tag biomolecules and labeling targets for cellular and molecular imaging workflows, including fixed-sample staining and immunofluorescence-style reagent preparation. Imaging teams rely on amine-reactive labeling to visualize proteins on surfaces, within extracellular matrices, or associated with biomolecular complexes, where covalent attachment improves retention during washes. The dye's spectral position supports blue/cyan-channel microscopy setups, enabling multiplexing strategies when paired with spectrally separated fluorophores.

3. Flow Cytometry Conjugate Preparation

ATTO 425-NHS ester is commonly incorporated into fluorescent labeling strategies for flow cytometry reagent development, particularly when fluorescently tagged proteins or antibodies are required for cell-surface or intracellular staining workflows. The NHS ester format supports covalent dye attachment to amine-containing biomolecules, helping reduce dye loss during sample processing and wash steps. Assay developers use ATTO 425-NHS ester to build consistent staining reagents for instrument-based fluorescence measurements and to generate calibration or reference conjugates for method optimization.

4. Fluorescent Labeling Of Peptides

ATTO 425-NHS ester is frequently used to label peptides and peptide-based probes for fluorescence tracking, binding studies, and biomolecular interaction assays. By targeting primary amines, the dye can be attached to peptide backbones and side chains to produce fluorescent peptide conjugates used in solution-phase assays and imaging experiments. Researchers often select ATTO 425-NHS ester when they want a direct route to fluorescent peptide reagents that can be used as tracers in binding, uptake, and localization studies, as well as in method development for fluorescence quantification.