Question

What are the types of endonucleases?

Answer 1

Endonucleases:

1. Endonucleases are the enzymes that are capable of cleaving/cutting the phosphodiester bond within a polynucleotide chain.
2. They are two types of endonucleases that are widely important. These include restriction enzymes and DNases.

Restriction enzyme:

1. It is a protein formed by bacteria that is capable of cleaving the DNA at specific sites.
2. This site is said to be the restriction site. The restriction enzymes protect the living bacteria from the bacteriophages.
3. They recognize and cut at the restriction sites of the bacteriophage, destroying its DNA. Restriction enzymes are quite an important tool for genetic engineering.
4. They could be isolated from the bacteria and then can be used in the laboratories.

DNase:

1. It is an enzyme that catalyzes the hydrolytic breaking of phosphodiester linkages in the DNA backbone.
2. They lead to the fragmentation and degradation of DNA.