An RNAse that is commonly used in research is RNAse A. RNAse A (bovine pancreatic ribonuclease A: PDB 2AAS, EC 22.214.171.124) is one of the hardiest enzymes in common laboratory usage; one method of isolating it is to boil a crude cellular extract until all enzymes other than RNAse A are denatured.
RNase P, another type of RNase, is currently under much research and is unique in that it is a ribozyme, a ribonucleic acid that acts as a catalyst in the same way that a protein based enzyme would. Its function is to cleave off an extra, or precurser, sequence of RNA on tRNA molecules. RNase P has two components: an RNA chain, called M1 RNA, and a polypeptide chain, or protein, called C5 protein. In vivo, both components are necessary for the ribozyme to function properly, but in vitro, the M1 RNA can act alone as a catalyst.