ribonuclease (pancreatic)

ri·bo·nu·cle·ase (pan·cre·at·ic)

(rī'bō-nū'klē-ās pan'krē-at'ik),
An enzyme isolated from the pancreas of ruminants that transfers the 3'-phosphate of a pyrimidine ribonucleotide residue in a polynucleotide from the 5'-position of the adjoining nucleotide to the 2'-position of the pyrimidine nucleotide itself (a transferase, endonuclease action), thus breaking the chain and forming a pyrimidine 2',3'-cyclic phosphate, then (or independently) hydrolyzing this phosphodiester to leave a pyrimidine nucleoside 3'-phosphate residue (phosphodiesterase action); used in cytochemistry to selectively degrade and remove RNA as a control for staining of RNA. End products are nucleoside 3'-phosphates and 3'-phosphooligonucleotides ending Cp or Up.
Synonym(s): RNase A, RNase I