terminal transferase

terminal transferase (terminal nucleotidyl transferase)

a DNA POLYMERASE that is capable of catalysing the addition of NUCLEOTIDES to the 3′-END of a single-stranded segment of a DNA molecule. The enzyme does not require a TEMPLATE strand, unlike normal polymerases. For example, the enzyme can be used to add a tail of ADENINE residues (poly(A) tail) to the 3′ends of a cloning VECTOR and a tail of THYMINE residues (poly(T) tail) to the 3′-ends of insert DNA When mixed, the adenines will anneal to the thymines by COMPLEMENTARY BASE PAIRING to generate a recombinant vector for use in gene cloning. This method is called homopolymer tailing.
References in periodicals archive ?
Identification of a specific telomere terminal transferase activity in Tetrahymena extracts.
A minor point may be effects from the terminal transferase activity of Taq polymerase that often adds a 3' nontemplate adenosine to the PCR-amplified product.
Therefore, this RNA-dependent activity, named terminal transferase or telomerase, was found to be a ribonucleoprotein complex that utilizes sequences of its own RNA component as a template for the de novo synthesis of telomeric DNA sequences.