Ribonuclease-A (RNase-A) from Bos taurus catalyses the depolymerisation of RNA. It does this by breaking down the 3'-5' phosphodiester linkages of single stranded RNA. It is specific for pyrimidine bases at the 3' position of the phosphodiester bond that is cleaved, and a purine at the 5' end. RNase-A also shows a preference for polynucleotide substrates over oligonucleotides.
Defined by 5 residues: HIS:A-12LYS:A-41HIS:A-119PHE:A-120ASP:A-121