Authors : M. BELJANSKI
Med. Sci. Res., 15, 1987, pp. 529-530.
Available in English only
ABSTRACT: Terminal deoxyribonucleotidyl transferase (TdT) (EC 18.104.22.168) was defined as a template independent DNA polymerase that binds deoxyribonucleoside-5′-monophosphates (dNMP) in sequential addition to the 3’OH end of the DNA initiator. TdT may exhibit its activity in the presence of oligodeoxyribopolymers. This enzyme has been found in embryonic calf thymus gland, cortical thymocytes, brain, primitive bone marrow cells, peripheral blood lymphocytes in certain forms of acute leukemia, neuroblastoma and retroviruses. A model was proposed according to which TdT may generate somatic mutations in the variable region of immunoglobulin genes. Recently, the mutagenic potential of TdT has been evaluated: TdT inserts noncomplementary bases during repair synthesis by DNA polymerase. The present work shows that purified and commercially available hepatitis-B antigen (vaccine) contains a very active TdT and ribonuclease (RNase).