Synta-Exo I exonuclease I degrades single-stranded DNA in the 3'5' direction, releasing deoxyribonucleoside 5'-monophosphate. Does not cleave DNA strands with terminal 3'-OH groups blocked by a phosphoryl or acetyl group. Active in PCR buffer.Isolated from Escherichia coli strain expressing the E. coli exonuclease I gene.Reaction conditions: 15-30 minutes at 37C, 10 units of Synta Exo I.Can be heat inactivated at 80C 15 minutes.