Endonuclease, hydrolyzes highly polymerized RNA, poly(U) and poly(C), and the dinucleotides CpA and UpA. Hydrolyzes 18S and 28S ribosomal RNA. More active towards rCA than rUA or rUG. Has cytotoxic activity against cultured human submaxillary gland carcinoma cells. Monomer. There are at least four different forms arising from glycan heterogeneity. Major (most represented) glycoform 1. Major (second-most represented) glycoform 2. Minor glycoform 3. Minor glycoform 4. Belongs to the pancreatic ribonuclease family.