RNA Polymerase

RNA Polymerases are enzymes involved in the production of RNA. After the annealing of a primer, RNA polymerases build a complementary strand of RNA from free nucleotides using a strand of DNA as a template. The active form is a complex consisting of multiple subunits known as the RNA polymerase holoenzyme (Molecular mass ~400 kilodaltons) .

In Eukaryotes some RNA polymerases include:

• RNA Polymerase I: Involved in the transcription of ribosomal RNA.
• RNA Polymerase II: Transcribes all genes that code for proteins.
• RNA Polymerase III: Involved in the transcription of transfer RNA (tRNA)