T4 DNA Polymerase catalyzes the synthesis of DNA in the 5' to 3' direction and requires the presence of template and primer. This enzyme has a 3' to 5' exonuclease activity which is much more active than that found in DNA Polymerase I (E. coli). Unlike E. coli DNA Polymerase I, T4 DNA Polymerase does not have a 5' to 3' exonuclease function.
