Endonuclease vs. Exonuclease — What's the Difference?

Endonucleases are enzymes that cleave the phosphodiester bond within a polynucleotide chain. Some, such as deoxyribonuclease I, cut DNA relatively nonspecifically (without regard to sequence), while many, typically called restriction endonucleases or restriction enzymes, cleave only at very specific nucleotide sequences.

Exonucleases are enzymes that work by cleaving nucleotides one at a time from the end (exo) of a polynucleotide chain. A hydrolyzing reaction that breaks phosphodiester bonds at either the 3′ or the 5′ end occurs.

Any of a group of enzymes that catalyze the hydrolysis of bonds between nucleotides in the interior of a DNA or RNA molecule.

Any of a group of enzymes that catalyze the hydrolysis of single nucleotides from the end of a DNA or RNA chain.

(enzyme) Any enzyme which catalyzes the cleavage of nucleic acids so as to produce variously sized fragments.

Any of a group of enzymes which cleave single nucleotides from the end of a polynucleotide (DNA or RNA) chain.

A nuclease that cleaves nucleic acids at interior bonds and so produces fragments of various sizes

A nuclease that releases one nucleotide at a time (serially) beginning at one of a nucleic acid