Terminal Deoxynucleotidyl Transferases

Terminal deoxynucleotidyl transferases (TdT) are polymerases used in molecular biology for adding deoxynucleotides to the 3' hydroxyl ends of DNA strands. The TdT reaction proceeds independently of a template and works irreversibly on both single- or double-stranded DNA, making the enzyme ideal for various DNA labeling applications. Examples include labeling with modified nucleotides, in situ labeling, and TUNEL labeling. TdT reagents are generally produced using recombinant methods and tested for the absence of contaminants, such as endonucleases and exonucleases. Visit the reagent supplier page for more information, including units of activity, validated applications, and more.