Thermo Scientific DyLight antibody labeling kits contain NHS ester-activated derivatives of our high-performance DyLight dyes. These kits are suitable for moderate scale labeling activities to fluorescently label antibodies and other proteins for use as probes for cellular imaging and other fluorescence detection methods.

  • High performance–DyLight dyes show bright fluorescence compared to classic dyes like FITC and rhodamine.
  • Specific–NHS ester-activated dye labels proteins and other molecules at primary amines (-NH2)
  • Optimized procedure–following the standard protocol results in antibodies with dye:protein ratios and recovery rates that help optimize fluorescence labeling and activity

DyLight antibody labeling kit components


Each Thermo Scientific DyLight antibody labeling kit contains all the necessary components for three 1-mg labeling reactions of any protein with a molecular weight of 50-150 kDa, and subsequent excess dye removal. The DyLight dyes included in these kits are activated with N-hydroxysuccinimide (NHS) esters, which is the most commonly used reactive group for labeling proteins. NHS esters react with primary amines to form stable covalent amide bonds and free NHS groups. The DyLight Dyes have absorption spectra ranging from 350 nm to 770 nm (Table 1). These reagents fluoresce across a broad pH range with excitation wavelengths that match the output of most common fluorescence instrumentation. Additionally, the water solubility of the DyLight reagents allows conjugations using a high dye-to-protein ratio without precipitation.

Our purification resin and spin columns help eliminate equilibration steps, and reduce the need to collect and monitor gravity-flow fractions. This system helps enable the efficient removal of excess dye and, helping you achieve better protein recovery and a more accurate determination of the dye-to-protein ratio.
Each kit includes:

  • DyLight Fluor NHS Ester, 3 x 65 μg vials
  • Borate Buffer (0.67M), 1 mL 
  • Purification Resin, 5 mL 
  • Microcentrifuge spin columns, 6 columns 
  • Microcentrifuge collection tubes, 12 tubes

DyLight Antibody Labeling Kit Protocol

The protocol for the DyLight Antibody Labeling Kits is simple, consisting of 2 main steps (Figure 1).


Figure 1. The protocol is simple and provides efficient labeling, exceptional clean-up and excellent antibody recovery.

Table 1. DyLight antibody labeling kit selection guide

DyLight Antibody Labeling KitEx/EmCat. No.SpectraComparable Dyes
DyLight 350353/43262275Description: Excitation and Emission Spectra of DyLight 350 FluorophoreAlexa Fluor 350, AMCA
DyLight 405400/42053020Description: Excitation and Emission Spectra of DyLight 405 FluorophoreAlexa Fluor 405, Cascade Blue
DyLight 488493/51853024Description: Excitation and Emission Spectra of DyLight 488 FluorophoreAlexa Fluor 488, fluorescein, FITC
DyLight 550562/57684530Description: Excitation and Emission Spectra of DyLight 550 FluorophoreAlexa Fluor 546, Alexa Fluor555, Cy3,TRITC
DyLight 594593/61853044Description: Excitation and Emission Spectra of DyLight 594 FluorophoreAlexa Fluor 594, Texas Red
DyLight 633638/65853046Description: Excitation and Emission Spectra of DyLight 633 FluorophoreAlexa Fluor 633
DyLight 650652/67284535Description: Excitation and emission spectra for DyLight 650Alexa Fluor 647,Cy5
DyLight 680692/71253056Description: Excitation and Emission Spectra of DyLight 680 FluorophoreAlexa Fluor 680, Cy5.5
DyLight 755754/77684538Description: Excitation and Emission Spectra of DyLight 750 FluorophoreAlexa Fluor 750
DyLight 800777/79453062Description: Excitation and Emission Spectra of DyLight 800 FluorophoreIRDye® 800