The degradation of pyrimidine ribonucleosides starts with either cytidine or uridine being transported into the cytosol. Cytidine is transported into the cytosol through an nupG transporter. Once inside the cytosol, it can be degraded into uridine by reacting with water and ahydrogen ion through a cytidine deaminase resulting in the release of ammonium and uridine. Uridine is transported into the cytosol through a nupG. Once in the cytosol , uridine can be degrade by reacting with phosphate through a uridine phosphorylase resulting in the release of an alpha-D-ribose-1-phosphate and a uracil. The alpha-D-ribose-1-phosphate reacts with an alpha-d-ribose 1,5-phosphomutase resulting in the release of a D-ribose 5-phosphate which can be incorporated into the pentose phosphate pathway.

pyrimidine ribonucleosides degradation References