Question

What is the difference between Type 1 and Type 2 restriction enzymes?

Answer 1

Type 1 restriction enzyme:

1. Restriction endonucleases are another name for type 1 restriction enzymes.
2. They are made up of two long strands of DNA that have been linked together.
3. These restriction enzymes identify certain DNA sequences and cleave them at a specific place.

Type 2 restriction enzyme:

1. Type 2 restriction enzymes are composed of four strands of DNA, two on each side.
2. They typically detect two nucleotides on a single strand of DNA and cleave it.

Difference between Type 1 and Type 2 restriction enzymes:

Type 1 restriction enzyme	Type 2 restriction enzyme
1. A multisubunit enzyme is composed of restriction and modification enzymes that cut DNA at random distances from their recognition regions.	1. The enzymes that cut DNA at certain locations near or inside their recognition sequences.
2. It is a multimer composed of three subunits.	2. It is a homodimer.
3. A restriction enzyme that also functions as a methylase.	3. It possesses distinct restriction and methylase activity.
4. Restriction and methylation are mutually exclusive processes.	4. Both restriction and methylation are distinct responses.
5. Has a restriction recognition site that is both bipartite and asymmetric.	5. Recognition site has a palindromic sequence of 4-6 bp.
6. Cleavage Site: Nonspecific, >1000 bp from recognition site.	6. Cleavage Site: The same as or near the recognition site.
7. ATP, Mg2+, and S-adenosyl methionine are restricted requirements.	7. Mg2+ is a restriction requirement.
8. DNA translocation occurs after cleavage.	8. There is no translocation.
9. EcoA 1, EcoB, EcoK I, and CfrA I are some examples.	9. EcoR I, BamH I, and Hind III are some examples.