Exonuclease

Definition

Exonuclease is an enzyme that removes nucleotides one at a time from the end of a DNA or RNA strand. It plays a crucial role in DNA repair, replication, and degradation.

5 Must Know Facts For Your Next Test

1. Exonucleases work by cleaving nucleotides from the ends of DNA or RNA molecules.
2. They are essential for proofreading and correcting errors during DNA replication.
3. Exonucleases can function in both the 3' to 5' and 5' to 3' directions.
4. They are different from endonucleases, which cut within the nucleotide chain.
5. Mutations affecting exonuclease activity can lead to genomic instability and diseases.

Review Questions

• What is the primary function of exonucleases during DNA replication?
• How do exonucleases differ from endonucleases?
• In which direction(s) can exonucleases remove nucleotides?

Related terms

DNA Polymerase: An enzyme that synthesizes new strands of DNA complementary to the template strand.

Endonuclease: An enzyme that cuts DNA internally at specific sites.

Proofreading: The process by which DNA polymerases correct errors in newly synthesized DNA.