TdT, Calf Thymus

Native TdT from calf thymus. Tdt is a DNA polymerase that catalyzes the addition of deoxynucleotides to the 3′ hydroxy terminus of either double of single stranded DNA in a template-independent manner.

The Calbiochem^® Terminal deoxynucleotidyl Transferase (TdT) is a DNA polymerase isolated from calf thymus. TdT catalyzes the addition of deoxynucleotides to the 3′-hydroxyl termini of either double or single stranded DNA molecules in a template independent manner. Although TdT preferentially adds deoxynucleotides to 3′-extensions, tailing onto 5′ overhangs or blunt ended double strands of DNA can also be achieved. TdT can be used for labeling DNA fragments and vectors with homopolymer tails and/or with modified deoxynucleotides such as biotin-dNTPs, 32P-dNTPs, cordycepin-dNTPs, or ddNTP.

DNA Labeling

775 Units in 50 mM potassium phosphate buffer, 1 mM B-mercaptoethanol, 50% glycerol, pH 7.2.

Following initial thaw, aliquot and freeze (-20°C).

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Michelson, A.M. and S.H. Orkin. 1982. J. Biol. Chem.257, 14773.
Roychoudhury, R. and R. Wu. 1980. Methods Enzymol.65, 43.
Nelson, T. and D. Brutlag. 1979. Methods Enzymol. 68, 41.
Roychoudhury, R., et al. 1976. Nucleic Acids Res.3, 101.
Bollum, F.J. 1974. In The Enzymes, 3rd edition (ed. P.D. Boyer), Vol. 10, 145. Academic Press, New York.

One unit is the amount of enzyme required to transfer 1 nmol of dAMP from dATP to the 3ʹ-OH terminus of d(A)50 in 60 min at 37°C.

CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany

Toxicity: Standard Handling (A)