onukleaasit

Onukleaasit are enzymes that cleave nucleic acid chains. They are broadly classified into deoxyribonucleases, which digest DNA, and ribonucleases, which digest RNA. These enzymes can be further categorized based on the type of bond they cleave, the ends of the nucleic acid chain they act upon, and whether they cleave single or double-stranded molecules.

Exonucleases degrade nucleic acids by removing nucleotides from the ends of the polynucleotide chain. In contrast, endonucleases cleave phosphodiester bonds within the nucleic acid chain, creating fragments. Some nucleases are specific for particular sequences or structures within the nucleic acid, while others are less selective.

Nucleases play crucial roles in various biological processes. In DNA repair, they help remove damaged or mismatched nucleotides. During DNA replication and transcription, they are involved in processing and modifying nucleic acid molecules. For instance, RNAse H specifically degrades RNA strands in DNA-RNA hybrids, which is important for various cellular functions.

In molecular biology research, nucleases are indispensable tools. Restriction endonucleases, a type of endonuclease, are widely used to cut DNA at specific recognition sites, enabling gene cloning and manipulation. DNases and RNases are also used in experimental procedures to remove or degrade specific nucleic acids. Furthermore, nucleases are involved in the programmed cell death pathway known as apoptosis, where they contribute to the breakdown of cellular components.