Terminal deoxynucleotidyl transferase, recombinant, catalyses the repetitive addition of mononucleotides to the terminal 3´-OH of a DNA initiator accompanied by the release of inorganic phosphate.

• Single-stranded DNA is preferred as an initiator
• Polymerisation is not template-dependent
• Addition of 1 mM Co²⁺ (as CoCl₂) in the reaction buffer allows the tailing of 3´ ends with varying degrees of efficiency
• Source: Recombinant E. coli strain

Applications:
Tailing reactions to add complementary homopolymer tails to DNA vectors and cDNA.
3´ end-labeling.
TUNEL assays.

5X Reaction buffer: 500 mM cacodylate buffer (pH 6,8 at 25 °C), 5 mM CoCl₂, 0,5 mM DTT.