DNA Polymerase I is a mezophilic, DNA-dependent DNA polymerase with inherent 3’→5′ and 5’→3′ exonuclease activity. Exhibits the 5’→3′ polymerase activity. Used to prepare radioactive probes by nick translation and random priming. Useful for end-labeling of DNA molecules with 3’ and 5’ protruding tails or blunt-ended.