Uridine Phosphorylase: An enzyme that catalyzes the transfer of ribose from uridine to orthophosphate, forming uracil and ribose 1-phosphate.Phosphorylases: A class of glucosyltransferases that catalyzes the degradation of storage polysaccharides, such as glucose polymers, by phosphorolysis in animals (GLYCOGEN PHOSPHORYLASE) and in plants (STARCH PHOSPHORYLASE).Uridine Kinase: An enzyme that catalyzes the phosphorylation of uridine and cytidine to uridine 5'-phosphate and cytidine 5'-phosphate, respectively. ATP, dUTP, dGTP, and dATP are effective phosphate donors. EC 220.127.116.11.Pentosyltransferases: Enzymes of the transferase class that catalyze the transfer of a pentose group from one compound to another.UridineUracilPurine-Nucleoside Phosphorylase: An enzyme that catalyzes the reaction between a purine nucleoside and orthophosphate to form a free purine plus ribose-5-phosphate. EC 18.104.22.168.Thymidine Phosphorylase: An enzyme that catalyzes the transfer of 2-deoxy-D-ribose from THYMIDINE to orthophosphate, thereby liberating thymidine.Floxuridine: An antineoplastic antimetabolite that is metabolized to fluorouracil when administered by rapid injection; when administered by slow, continuous, intra-arterial infusion, it is converted to floxuridine monophosphate. It has been used to treat hepatic metastases of gastrointestinal adenocarcinomas and for palliation in malignant neoplasms of the liver and gastrointestinal tract.Phosphorylase Kinase: An enzyme that catalyzes the conversion of ATP and PHOSPHORYLASE B to ADP and PHOSPHORYLASE A.Ribosemonophosphates: Ribose substituted in the 1-, 3-, or 5-position by a phosphoric acid moiety.Phosphorylase b: The inactive form of GLYCOGEN PHOSPHORYLASE that is converted to the active form PHOSPHORYLASE A via phosphorylation by PHOSPHORYLASE KINASE and ATP.Phosphorylase a: The active form of GLYCOGEN PHOSPHORYLASE that is derived from the phosphorylation of PHOSPHORYLASE B. Phosphorylase a is deactivated via hydrolysis of phosphoserine by PHOSPHORYLASE PHOSPHATASE to form PHOSPHORYLASE B.Hymenolepis: A genus of small tapeworms of birds and mammals.Pyrimidine Nucleosides: Pyrimidines with a RIBOSE attached that can be phosphorylated to PYRIMIDINE NUCLEOTIDES.Glycogen Phosphorylase: An enzyme that catalyzes the degradation of GLYCOGEN in animals by releasing glucose-1-phosphate from the terminal alpha-1,4-glycosidic bond. This enzyme exists in two forms: an active phosphorylated form ( PHOSPHORYLASE A) and an inactive un-phosphorylated form (PHOSPHORYLASE B). Both a and b forms of phosphorylase exist as homodimers. In mammals, the major isozymes of glycogen phosphorylase are found in muscle, liver and brain tissue.