Table of Contents
What is an endonuclease vs exonuclease?
Restriction endonucleases are enzymes that recognise DNA sequences, scan the sequence and cleave the fragment around or within that sequence. Exonucleases are enzymes that cleave the polynucleotide sequence either from the 5′ end or the 3′ end, one at a time. It is found only in prokaryotes.
What are exonuclease activities?
Exonucleases are enzymes that catalyze the removal of nucleotides in either the 5-prime to 3-prime or the 3-prime to 5-prime direction from the ends of single-stranded and/or double-stranded DNA. Removal of nucleotides is achieved by cleavage of phosphodiester bonds via hydrolysis.
Which has 5 exonuclease activity?
DNA polymerase I
Exonuclease II is associated with DNA polymerase I, which contains a 5′ exonuclease that clips off the RNA primer contained immediately upstream from the site of DNA synthesis in a 5′ → 3′ manner.
How can you distinguish between endonuclease and exonuclease?
The main difference between endonucleases and exonucleases is that endonuclease cleaves nucleic acid strand at the middle whereas exonuclease cleaves nucleic acid strands from the ends. The major role of nucleases inside the cell is to take part in the DNA repair mechanisms.
Which of the following posses both 5 → 3 exonuclease and 3 → 5 exonuclease activity?
DNA polymerase I is a single polypeptide chain with 928 amino acids and molecular weight of 109 kDa. It has three sites, which provide three distinct catalytic activities: 3′ to 5′ exonuclease, 5′ to 3′ exonuclease, and 5′ to 3′ polymerase.
What is the difference between exonuclease and endonuclease Class 12?
Exonucleases refer to nuclease enzymes that separates the nucleotides from the ends. Endonucleases cut the phosphodiester bond present in the polynucleotide from the centre.
What is the definition of an exonuclease?
Definition of exonuclease : an enzyme that breaks down a nucleic acid by removing nucleotides one by one from the end of a chain — compare endonuclease.