Restriction Endonuclease is a type of restriction enzyme that cuts within the DNA at a specific site. This enzyme acts as an important tool in genetic engineering for cutting DNA sequences from a specific site. They play an important role in gene manipulation. Exonuclease refers to an enzyme that cleaves. polynucleotide chain from the end of the chain by removing the nucleotides one by one. They cleave nucleic acids at the ends and result in single nucleotides. They form blunt ends.