Required for replicative DNA synthesis. This DNA polymerase also exhibits 3' to 5' exonuclease activity. a 2'-deoxyribonucleoside 5'-triphosphate + DNA(n) = diphosphate + DNA(n+1) Mutant azp12 has a form of DNA polymerase III resistant to hydroxyphenylazopyrimidines. Belongs to the DNA polymerase type-C family. PolC subfamily.