A non-template-directed DNA polymerase normally found in vertebrate thymus and bone marrow. It catalyses the elongation of oligo- or polydeoxynucleotide chains and is widely used as a tool in the differential diagnosis of acute leukaemias in man.
Chemical name: Nucleoside-triphosphate:DNA deoxynucleotidylexotransferase
Registry number: EC 2.7.7.31
(12 Dec 1998)