Pseudouridine-18O is the 18O labeled Pseudouridine (HY-113061). Pseudouridine is an isomer of the nucleoside uridine, and the most abundant modified nucleoside in non-coding RNAs. Pseudouridine in rRNA and tRNA can fine-tune and stabilize the regional structure and help maintain their functions in mRNA decoding, ribosome assembly, processing and translation.