Pseudouridine Residues as Substrates for Serum Ribonucleases.

In clinical uses, RNA must maintain its integrity in serum that contains ribonucleases (RNases), especially RNase 1, which is a human homolog of RNase A. These omnipresent enzymes catalyze the cleavage of the P-O bond on the 3' side of pyrimidine residues. Pseudouridine (Ψ) is the most abundant modified nucleoside in natural RNA.