ATTO 550 NHS ester | CAS 1005770-00-2

ATTO 550 NHS ester is a reactive fluorescent dye designed for efficient covalent labeling of primary amines on proteins, peptides, and other amine-containing biomolecules. As an NHS ester, it enables straightforward preparation of fluorescent conjugates for microscopy and fluorescence-based assays, with ATTO 550 providing strong signal in the orange-red spectral region. This reagent is widely used in chemical biology and bioimaging workflows where stable dye conjugation is required for visualization, tracking, and quantitative readouts.

1. Protein Conjugation Labeling

ATTO 550 NHS ester is frequently used by protein chemistry and chemical biology groups to generate fluorescently labeled antibodies, enzymes, and purified proteins for downstream imaging and assay development. Researchers commonly react the NHS ester with lysine residues or N-terminal amines to prepare conjugates for fluorescence microscopy, gel-based fluorescence readouts, and fluorescence spectroscopy. The resulting ATTO 550-labeled biomolecules are useful when a bright, photostable orange-red fluorophore is needed to track binding, localization, or reaction outcomes in labeled protein systems.

2. Fluorescence Microscopy Staining

ATTO 550 NHS ester supports cellular and molecular imaging workflows where amine-reactive fluorescent labeling is used to visualize biomolecular structures and interactions. Lab teams use ATTO 550 conjugates as labeling reagents for fixed-cell staining protocols, immunofluorescence workflows, and multicolor imaging experiments that require an orange-red emission channel. By preparing dye-labeled secondary reagents or directly labeling target proteins prior to staining, researchers can standardize fluorophore loading and improve consistency across microscopy experiments.

3. Flow Cytometry Dye Conjugates

ATTO 550 NHS ester is used in flow cytometry reagent development to produce fluorescent conjugates for labeling cell-surface or intracellular proteins via amine coupling strategies. Typical workflows include preparing dye-labeled antibodies, protein binders, or affinity reagents that target specific cellular markers, followed by analysis on standard flow cytometers equipped for the ATTO 550 emission range. This approach is particularly common in assay development and phenotyping studies where stable covalent dye attachment helps maintain signal during staining and washing steps.

4. Fluorescence Bioassay Reagent Development

ATTO 550 NHS ester is also applied in fluorescence assay development to create labeled components for quantitative readouts, including enzyme-linked fluorescence formats and binding assays that rely on fluorescent reporter conjugates. Researchers prepare ATTO 550-labeled proteins, peptides, or other amine-bearing reagents to serve as detection reporters, enabling consistent assay construction for endpoint fluorescence measurements. In molecular imaging reagent development, the dye conjugates produced from ATTO 550 NHS ester are often integrated into probe libraries where covalent attachment to biomolecular building blocks is required for reproducible assay performance.