Cyanine dye labeling reagents containing isothiocyanate groups

Cytometry. 1989 Jan;10(1):11-9. doi: 10.1002/cyto.990100104.


New isothiocyanate derivatives of cyanine dyes were synthesized as fluorescent covalent labeling reagents for proteins and other biomolecules. These dyes have maximum absorbance in the red and near infrared regions of the spectrum, have high extinction coefficients and have adequate quantum yields. Incorporating two alkyl sulfonate groups in the dye structures increases their water solubility, which is beneficial for labeling biological molecules in aqueous solution. Reactivities of proteins with these new cyanines are similar to their reactivities with fluorescein isothiocyanate. These new labeling reagents are complementary to the fluorescein and rhodamine reagents, expanding the possibilities of multicolor analyses. Sheep anti-mouse-IgG antibody was labeled with a pentamethine cyanine dye (CY5.8-ITC) and used with a fluoresceinated antibody as a second reagent for detecting human T-cell subsets by flow cytometry.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antibodies / metabolism
  • Carbocyanines* / analysis
  • Carbocyanines* / metabolism
  • Flow Cytometry / methods
  • Fluorescent Dyes* / analysis
  • Fluorescent Dyes* / metabolism
  • Humans
  • Immunoglobulins / metabolism
  • Indicators and Reagents
  • Isothiocyanates*
  • Lymphocytes / metabolism
  • Proteins / metabolism
  • Quinolines*
  • Spectrometry, Fluorescence / methods
  • Terminology as Topic
  • Thiocyanates / metabolism*


  • Antibodies
  • Carbocyanines
  • Fluorescent Dyes
  • Immunoglobulins
  • Indicators and Reagents
  • Isothiocyanates
  • Proteins
  • Quinolines
  • Thiocyanates
  • isothiocyanic acid