Terminal Deoxynucleotidyl Transferase

Thermo Scientific Terminal Deoxynucleotidyl Transferase (TdT) is a template-independent DNA polymerase that catalyzes the repetitive addition of deoxyribonucleotides to the 3'-OH of oligodeoxyribonucleotides and single-stranded and double-stranded DNA. TdT requires an oligonucleotide of at least three nucleotides to serve as a primer. With RNA as template TdT shows variable performance which strongly depends upon the tertiary structure of acceptor RNA 3'-end and the nature of nucleotide. Generally, it is lower than using DNA as a template.

Highlights
• Incorporates modified nucleotides (e.g., fluorescein-, biotin-, aminoallyl-labeled nucleotides)

Applications
• Production of synthetic homo- and heteropolymers
• Homopolymeric tailing of linear duplex DNA with any type of 3'-OH terminus
• Oligodeoxyribonucleotide and DNA labeling
• 5'-RACE (Rapid Amplification of cDNA Ends)
• In situ localization of apoptosis

Note
Due to the presence of CoCl2, the TdT Reaction Buffer is incompatible with downstream applications. It is necessary to remove CoCl2 from the reaction mixture by spin column or phenol/chloroform extraction and subsequent ethanol precipitation.