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3' EndTag™ DNA End Labeling System (MB-9002)

The product has been discontinued

Please consider the following as potential substitutes: MB-9001. 5′ EndTag DNA/RNA Labeling Kit. Or contact Technical Support @ [email protected] for assistance in finding alternative.


3′ end labeling is the preferred method for oligonucleotide labeling if the terminal phosphate at the 5′ end must be preserved.

The 3′ EndTag System enables simple and uniform labeling of blunt, overhanging, or recessed 3′ ends of DNA. Using this system, a variety of fluorescent dyes, haptens, or affinity tags can be covalently attached to the 3′ end using thiol-specific chemistry. Additionally, labels containing thiol-reactive groups (maleimides, iodoacetamides, etc.) can easily be incorporated.


Unit Size1 kit
Target for LabelingDNA
Required Reactive Group3′ -OH group of DNA
Tag/Group IncorporatedThiol
Safety TitleWARNING: NA –

Kit Components

What’s in the box?

The 3′ EndTag Labeling Kit is designed to perform 20 labeling reactions of up to 0.5 nmols of 3′ ends (e.g. about 4.2 μg of a 25 base oligonucleotide) per reaction. This kit includes:

  • Terminal Transferase (TdT)
  • SH-GTP
  • 10x TdT buffer
  • Precipitant

*Note: This kit requires Thiol-reactive labeling reagent, which is not included in the kit and must be purchased separately. Labels suitable for this kit include:

Note regarding shipping: This item is shipped on wet ice and therefore requires additional shipping charges.


Technical Information

End labeling is a preferred method for applications in which an internal label might interfere with hybridization or sequence specific protein binding.

5′ or 3′ EndTag labeled nucleic acids can be used for applications such as DNA hybridization, PCR, in situ hybridization, the binding of capture probes to affinity matrices, or electrophoretic mobility shift assays (EMSA). Short oligonucleotides are labeled more efficiently with these systems than with other methods. In addition, end labeling of oligonucleotides is an economical alternative to having labels inserted during synthesis.

Labeling time is about 1 hour with very little hands-on time required.

3′ EndTag Labeling Kit

Labeling using the 3′ EndTag Labeling Kit is achieved in two steps:

  1. Terminal deoxynucleotidyl transferase (TdT) incorporates the thiol-containing nucleotide (SH-GTP) onto the 3′ end.
  2. Thiolated DNA is coupled with a thiol-reactive label.


Note: Thiol-reactive label is not included in the kit and must be purchased separately.

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