Endonuclease V is a repair enzyme found in E. coli that recognizes deoxyinosine, a deamination product of deoxyadenosine in DNA. Endonuclease V, often called deoxyinosine 3 endonuclease, recognizes DNA containing deoxyinosines (paired or not) on double-stranded DNA, single-stranded DNA with deoxyinosines and to a lesser degree, DNA containing abasic sites (ap) or urea, base mismatches, insertion/deletion mismatches, hairpin or unpaired loops, flaps and pseudo-Y structures. It is believed that Endonuclease V needs another protein to repair the DNA, as it does not remove the deoxyinosine or the damaged bases. Endonuclease V cleaves the second phosphodiester bonds 3' to the mismatch of deoxyinosine, leaving a nick with 3'-hydroxyl and 5'-phosphate.