endonukleaase

Endonuclease refers to an enzyme that cleaves the phosphodiester bond within a polynucleotide chain. This distinguishes them from exonucleases, which cleave nucleotides from the end of a polynucleotide chain. Endonucleases can be found in both prokaryotic and eukaryotic organisms, and they play crucial roles in various cellular processes.

One of the most well-known types of endonucleases are restriction endonucleases, often called restriction enzymes. These enzymes are vital tools in molecular biology, used to cut DNA at specific recognition nucleotide sequences. This ability to precisely cut DNA allows for the manipulation and analysis of genetic material. For instance, restriction enzymes are used in DNA cloning, gene mapping, and the creation of recombinant DNA.

Beyond their use in biotechnology, endonucleases are essential for DNA repair mechanisms within cells. They can remove damaged or modified bases from the DNA backbone, preventing mutations and maintaining genomic integrity. Some endonucleases are also involved in programmed cell death, or apoptosis, where they contribute to the dismantling of cellular components. The specific cleavage sites and mechanisms of action vary widely among different types of endonucleases, reflecting their diverse biological functions.