Читать книгу Plant Nucleotide Metabolism - Hiroshi Ashihara - Страница 20

A pyrimidine nucleoside consists of a pyrimidine base and a five-carbon sugar, either ribose or deoxyribose. Uridine (39) and cytidine (40) are produced as catabolites of pyrimidine ribonucleotides and RNA. Thymidine (41) is a catabolite of DNA. There are many modified bases in RNA, including those contained in the nucleosides, pseudouridine (5-ribosyluracil) (42), and dihydrouridine (43). Pseudouridine is an isomer of the nucleoside uridine (39) in which the uracil is attached via a carbon–carbon linkage instead of a nitrogen–carbon glycosidic bond. It is the most prevalent of the over 100 different modified nucleosides found in RNA.