DNA Polymerase I (or
Pol I) is an
enzyme that participates in the process of
DNA replication. Discovered by
Arthur Kornberg in 1956, it was the first known
DNA polymerase (and, indeed, the first known of any kind of
polymerase). It was initially characterized in
E. coli and is ubiquitous in
prokaryotes. In
E. coli and many other bacteria, the
gene that encodes Pol I is known as
polA. The
E. coli form of the enzyme is composed of 928 amino acids, and is an example of a
processive enzyme—it can sequentially catalyze multiple polymerisations.