Exonuclease I (ExoI) degrades single-stranded DNA in a 3' to 5' direction. It releases deoxyribonucleoside 5'-monophosphates in a stepwise manner and leaves 5'-terminal dinucleotides intact. It does not cleave DNA strands with terminal 3'-OH groups blocked by phosphoryl or acetyl groups.
E. coli strain
• Primer removal from PCR mixtures
• Removal of single-stranded DNA containing a 3'-hydroxyl terminus from nucleic acid mixtures
• Assay for the presence of single-stranded DNA with a 3'-hydroxyl terminus