From bovine thymus.
- 3'-end labeling of DNA
- Template independent
- Production of synthetic homo- and heteropolymers
- addition of homopolymer tails to vectors and cDNA
Terminal deoxynucleotidyl transferase (TdT) is a primer-dependent DNA polymerase that catalyzes the repeated addition of mononucleotide units from a deoxynucleotide triphosphate to the terminal 3' hydroxyl of single or double-stranded DNA. The reaction is affected by the type of bases added (dATP, dCTP, dGTP and dTTP), the type of divalent cations in the buffer (Mn2+, Co2+, Mg2+), and the terminal structure of DNA (3'-protruding -OH end, blunt end, 3'-recessed -OH end). Thus, it is necessary to find the optimum conditions for each reaction. This polymerization releases inorganic pyrophosphate . TdT is widely used in tailing reactions (cDNA and DNA vector tailing). This enzyme is also used for labeling 3' OH ends of DNA fragments.
|Storage:||KPO4 100 mM pH 7.2, DTT 1 mM, Glycerol 50%. Store at -20°C|
|Unit Definition:||One unit of TdT catalyzes the addition of one nmol deoxyadenylate in one hour onto a p(dT)6 oligodeoxyribonucleotide at 37°C|
|Incubation buffer 1x:||Cacodylate K 140 mM pH 7.2, CoCl2 1 mM, ZnSO4 0.33 mM, BSA 10 mg/ml.|
|Purity:||Free from detectable nuclease activity.|
Under the conditions described above, 70-120 dA or dT residues, or 15-30 dC or dG residues per 3'-OH end of DNA can be added.
Concentration: 15 U/µl
Supplied with 5x incubation buffer