Question

What are restriction enzymes? Give examples.

Answer 1

Restriction enzymes:

1. Restriction enzymes identify particular DNA sequences and cut them in a controlled way.
2. These enzymes also referred to as restriction endonucleases, are a component of the genetic engineering toolkit and enable gene cloning.
3. Naturally, these are bacterial defense mechanisms against alien DNA.
4. As endonucleases, they have the ability to cleave foreign DNA from the inside and render it useless.
5. The fact that each restriction enzyme has a distinct restriction site makes them appropriate for gene cloning.
6. An enzyme especially identifies this short DNA sequence, which typically has 4–8 nucleotide pairs.
7. When read from 5′ to 3′, both strands of DNA will have an identical sequence, which is recognized by the majority of restriction enzymes.
8. Once this recognition has taken place, the enzyme begins to cleave the sugar-phosphate backbone at specified locations, usually within the restriction site.
9. Therefore, when it is digested by a restriction enzyme, several smaller DNA fragments—called restriction fragments—are produced
10. Example of restriction enzymes includes EcoRI and smaI.