RNA polymerase mechanism

In 1955, Marianne Grunberg-Manago and Severo Ochoa reported the isolation of an enzyme that catalyzed the synthesis of RNA.But in 1960; the true enzyme was identified by 4 separate groups: Sam Weiss at the University of Chicago, Jerard Hurwitz, A. Stevens and J. Bonner. This enzyme required a template, used all four rNTPs as substrates and synthesized a product with a composition similar to that of the template, and it required Mg++. DNA-directed RNA polymerase catalyzes the synthesis of RNA on a DNA template following similar nucleophilic attack chemistry as DNA polymerase.

The chemical reaction catalyzed by RNA polymerases.