Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
Exonucleolytic cleavage in the 3'- to 5'- direction to yield nucleoside 5'-phosphates (exonuclease type a)
This enzyme has preference for single-stranded substrate.
References
Laskowski M (1966). ", Sr. Pancreatic deoxyribonuclease I". In Cantoni GL, Davies DR (eds.). Procedures in Nucleic Acid Research. New York: Procedures in Nucleic Acid Research. pp. 85–101.