Key Difference – Endonuclease vs Exonuclease Before looking at the difference between endonuclease and exonuclease, it is important to know what exactly a nuclease is. A nuclease is an enzyme capable of cleaving phosphodiester bonds between nucleotides in nucleic acids. Endonuclease and exonuclease are two classifications of nucleases. The key difference between endonuclease and […]