RNase J, also called Ribonuclease J, is a prokaryotic ribonuclease which plays a key part in RNA processing and in RNA degradation. It can act as an endonuclease which is specific for single-stranded regions of RNA irrespective of their sequence or location, and as a processive 5' exonuclease which only acts on substrates having a single phosphate or a hydroxyl at the 5' end. Many bacterial species have only one RNase J, but some, such as Bacillus subtilis, have two. Members of this subgroup belong to the MBL-fold metallo-hydrolase superfamily which is comprised mainly of hydrolytic enzymes which carry out a variety of biological functions.
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