The enzyme required for DNA replication is DNA polymerase. All living organisms which have DNA as their genetic material require DNA polymerase enzyme.
We will begin our discussion of DNA polymerases with the E. coli enzymes. This prokaryote has 5 different kinds of DNA polymerase: DNA pol I, DNA pol II, DNA pol III, DNA pol IV and DNA pol V. It is DNA pol I, which was discovered by A. Kornberg and also named Kornberg Enzyme. However, DNA pol I is not suited for replication of large E. coli chromosome. The reasons for this would be discussed in a later post. In the early 1970s, DNA pol II and DNA pol III were discovered. DNA pol IV and DNA pol V were discovered much later, in 1999. DNA pol III is the principal replication enzyme in E. coli. DNA pol II is involved in DNA repair. DNA polymerases IV and V are also involved in a special form of DNA repair. “DNA pol I performs a host of clean-up functions during replication, repair and recombination” (Lehninger Principles of Biochemistry, Nelson and Cox, 3rd edition). It is not the primary enzyme of replication in the prokaryote.