Exoribonuclease

An exoribonuclease is an exonuclease ribonuclease, which are enzymes that degrade RNA by removing terminal nucleotides from either the 5' end or the 3' end of the RNA molecule.

Enzymes that remove nucleotides from the 5' end are called 5'-3' exoribonucleases, and enzymes that remove nucleotides from the 3' end are called 3'-5' exoribonucleases.

As the phosphorolytic enzymes use inorganic phosphate to cleave bonds they release nucleotide diphosphates, whereas the hydrolytic enzymes (which use water) release nucleotide monosphosphates.

Exoribonucleases exist in all kingdoms of life, the bacteria, archaea, and eukaryotes.

Exoribonucleases can be single proteins (such as RNase D or RNase PH) but also can be complexes of multiple proteins, such as the exosome complex (in which four of the major exoribonuclease families are represented).