Cy3-Transferrin is a fluorescent labeling reagent composed of the Cy3 fluorescent dye and Transferrin. The Cy3 fluorophore is commonly applied in immunolabeling, nucleic acid labeling, fluorescence microscopy, and flow cytometry, with a peak emission wavelength of approximately 562-570 nm. Transferrin is a plasma glycoprotein and serves as a target ligand for the transferrin receptor, facilitating iron binding and transport.