:Exodeoxyribonuclease I

{{Infobox enzyme

| Name = Exodeoxyribonuclease I

| EC_number = 3.1.11.1

| CAS_number = 9037-46-1

| GO_code =

| image =

| width =

| caption =

}}

Exodeoxyribonuclease I (EC 3.1.11.1, Escherichia coli exonuclease I, E. coli exonuclease I, exonuclease I) is an enzyme{{cite journal | vauthors = Blakesley RW, Dodgson JB, Nes IF, Wells RD | title = Duplex regions in "single-stranded" phiX174 DNA are cleaved by a restriction endonuclease from Haemophilus aegyptius | journal = The Journal of Biological Chemistry | volume = 252 | issue = 20 | pages = 7300–6 | date = October 1977 | doi = 10.1016/S0021-9258(19)66969-3 | doi-access = free | pmid = 71298 }}{{cite journal | title = Excision of thymine dimers and other mismatched sequences by DNA polymerases of Escherichia coli | vauthors = Kelley RB, Atkinson MR, Huberman JA, Kornberg A |journal = Nature |year = 1969 |volume = 224 | issue = 5218 |pages = 495–501 |doi=10.1038/224495a0| bibcode = 1969Natur.224..495K }}{{cite journal | vauthors = Lehman IR, Nussbaum AL | title = The deoxyribonucleases of Escherichia coli. V. On the specificity of exonuclease I (phosphodiesterase) | journal = The Journal of Biological Chemistry | volume = 239 | pages = 2628–36 | date = August 1964 | issue = 8 | doi = 10.1016/S0021-9258(18)93898-6 | doi-access = free | pmid = 14235546 }} that catalyses the following chemical reaction:

: Exonucleolytic cleavage in the 3′- to 5′-direction to yield nucleoside 5′-phosphates

Preference for{{clarify|need complete sentence|date=October 2016}} single-stranded DNA. The Escherichia coli enzyme hydrolyses glucosylated DNA.