sulfo-Cyanine5 hydrazide | CAS 2055138-61-7

Sulfo-Cyanine5 hydrazide is a water-soluble cyanine dye hydrazide designed for fluorescence labeling of aldehyde-bearing biomolecules and materials, enabling bright far-red imaging readouts in labeling workflows. The hydrazide functional group reacts with carbonyls to form stable hydrazone linkages, which supports conjugate construction for microscopy, gel-based analysis, and fluorescence-based assay development.

1. Aldehyde Biomolecule Labeling

Sulfo-Cyanine5 hydrazide is used to fluorescently tag aldehyde-functionalized proteins, peptides, and carbohydrate-modified biomolecules in chemical biology and glycoconjugate research. Researchers commonly incorporate it after mild oxidation steps (e.g., converting glycan or carbohydrate motifs to aldehydes) to generate far-red fluorescent conjugates for tracking binding, uptake, and localization in complex biological mixtures. The sulfonate-containing dye structure supports aqueous handling during conjugate preparation and downstream fluorescence readouts, making it a practical reagent for preparing labeled reagents for microscopy and fluorescence assays.

2. Fluorescence Microscopy Tracing

Sulfo-Cyanine5 hydrazide-labeled conjugates are frequently employed as far-red fluorescent tracers to visualize biomolecule distribution in fixed-cell imaging workflows and in microscopy-based studies of labeled targets. In cell biology laboratories, the dye is used to follow the localization of carbonyl-containing biomolecule derivatives, including glycoconjugates and oxidized biomaterials, where far-red emission helps reduce background from cellular autofluorescence. Labeling with this hydrazide is also leveraged for multi-step probe construction, such as generating fluorescent affinity reagents or imaging-compatible conjugates for confocal and widefield fluorescence microscopy.

3. Gel Electrophoresis and Blotting

Sulfo-Cyanine5 hydrazide is applied in fluorescence-based protein analysis workflows where aldehyde-containing samples are labeled prior to electrophoresis or blot imaging. In proteomics and analytical biochemistry, the reagent enables sensitive visualization of labeled proteins and conjugates using far-red fluorescence detection, supporting workflows such as monitoring labeling efficiency, comparing relative labeling across samples, and validating conjugate formation in experimental optimization. Because the dye is water-soluble and attaches through hydrazone formation to carbonyl groups, it is commonly used to generate fluorescent standards and to support quantitative imaging on fluorescence-capable gel documentation systems.

4. Fluorescent Probe Conjugate Building

Sulfo-Cyanine5 hydrazide serves as a dye-building block for constructing fluorescent probe conjugates used in assay and molecular imaging development. Chemical biology groups use the hydrazide to introduce a far-red fluorophore onto aldehyde-functional linkers, affinity reagents, or scaffold molecules, enabling downstream incorporation into larger probe architectures such as labeled binding reagents and imaging-compatible platforms. This approach is particularly useful when a stable carbonyl-reactive handle is needed to attach a cyanine fluorophore to an intermediate containing aldehyde functionality, supporting consistent probe preparation for fluorescence readouts in research assays.