(i) DNA-dependent DNA polymerase - Uses DNA template to catalyse the polymerisation of deoxynucleotides.
(ii) DNA-dependent RNA polymerase- Catalyses transcription of all types of RNAs in bacteria.
(iii) In eukaryotes there are three types of DNA- dependent RNA polymerase:
(a) RNA polymerase I- Transcribes rRNAs
(b) RNA polymerase II- Transcribes precursor of mRNA i.e. hmDNA
(c) RNA polymerase III-Transcribes tRNA, srRNA and snRNAS. .
(iv) Reverse transcriptase for the synthesis of complementary DNA over RNA template.