Table 1.12 Amine-reactive, ultraviolet light–excitable fluorophores for labeling proteins and nucleic acids.

FluorophoreAbs *Em *Amine-Reactive DyesProtein and Nucleic Acid Labeling KitsNotes
Alexa Fluor 350346442A10168 (SE)A20180 (Ab)
A10170 (P)
Z25000 (Z)
Z25100 (Z)
Z25200 (Z)
Z25300 (Z)
Z25400 (Z)
  • Higher fluorescence per attached dye than AMCA
  • Protein conjugates emit at slightly shorter wavelengths than AMCA or AMCA-X
Alexa Fluor 405402421A30000 (SE)
A30100 (SE)
Z25013 (Z)
Z25113 (Z)
Z25213 (Z)
Z25313 (Z)
  • Cascade Blue derivative containing a spacer between the fluorophore and the reactive SE
  • Near-perfect match to the 405 nm violet diode laser
Alexa Fluor 430433539A10169 (SE)A10171 (P)
Z25001 (Z)
Z25301 (Z)
  • Extremely large Stokes shift
  • Fills spectral gap between green- and yellow-fluorescent dyes
AMCA-X353442A6118 (SE) 
  • Widely used blue-fluorescent labeling dye
  • Compact structure
Bimane380458B30250 (COOH) 
  • Blue-fluorescent dye
  • Small size
Cascade Blue400420C2284 (AA) 
  • Resistant to quenching upon protein conjugation
  • Trisulfonated pyrene
470 (1)
475 (2)
D126 (COOH)
D1421 (COOH)
D374 (SE)
D1412 (SE)
D10166 (ITC)
  • Longer-wavelength alternatives to AMCA
445 (3)
455 (4)
H185 (COOH)
H1428 (COOH)
H1193 (SE)
  • pH-sensitive fluorescence
  • Compact structure
Marina Blue365460M10165 (SE) 
  • Optimal for 365 nm excitation sources
Methoxycoumarin358410M1420MP (COOH)
M1410 (SE)
  • pH-insensitive fluorescence
  • Compact structure
Pacific Blue410455P10163 (SE)A10478 (APEX)
P30013 (Ab)
P30012 (P)
Z25041 (Z)
Z25341 (Z)
  • Longer-wavelength alternative to the Alexa Fluor 350 and AMCA-X dyes
  • Excited with the 405 nm violet diode laser
Pacific Orange400551P30253 (SE)P30014 (Ab)
P30016 (P)
Z25256 (Z)
Z25257 (Z)
  • Excited with the 405 nm violet diode laser
  • Compatible with the Pacific Blue dye for two-color analysis using the blue diode laser

* The absorption (Abs) and fluorescence emission (Em) maxima, in nm, listed in this table are for the goat anti–mouse IgG antibody or dextran conjugates in aqueous buffer.

(1) Spectral maxima for D374.
(2) Spectral maxima for D1412.
(3) Spectral maxima for H1193.
(4) Spectral maxima for 7-hydroxy-4-methylcoumarin-3-acetic acid, succinimidyl ester.

(AA) = Acetyl azide.
(Ab) = Antibody Labeling Kit (Kits for Labeling Proteins and Nucleic Acids—Section 1.2).
(APEX) = APEX Antibody Labeling Kit (Kits for Labeling Proteins and Nucleic Acids—Section 1.2).
(COOH) = Carboxylic acid.
(ITC) = Isothiocyanate.
(P) = Easy-to-Use Protein Labeling Kit (Kits for Labeling Proteins and Nucleic Acids—Section 1.2).
(SE) = Succinimidyl ester.
(Z) = Zenon Antibody Labeling Kit (Zenon Technology: Versatile Reagents for Immunolabeling—Section 7.3).

For Research Use Only. Not for use in diagnostic procedures.