title: Identification of a novel human uridine phosphorylase.
abstract: Uridine phosphorylase catalyzes the reversible phosphorylytic cleavage of uridine and deoxyuridine to uracil and ribose- or deoxyribose-1-phosphate. The enzyme has an important role in the metabolism of pyrimidine analogs used in cancer chemotherapy. The cDNA of a novel 317 amino acid human uridine phosphorylase approximately 60% identical to the previously identified human uridine phosphorylase was cloned. The novel enzyme, named uridine phosphorylase-2 (UPase-2), showed broad substrate specificity and accepted uridine, deoxyuridine, and thymidine as well as the two pyrimidine nucleoside analogs 5-fluorouridine and 5-fluoro-2(')-deoxyuridine. The human UPase-2 gene was mapped to chromosome 2q24.1 and the 2.2-kb mRNA was predominantly expressed in kidney. The mouse UPase-2 cDNA was also identified and shown to be predominantly expressed in liver. The identification of a novel uridine phosphorylase with broad substrate specificity is important for studies on both nucleoside metabolism as well as for studies on the pharmacological mechanisms of therapeutic pyrimidine nucleoside analogs.
authors.affiliation: Division of Clinical Virology F68, Karolinska Institute, Huddinge University Hospital, Stockholm, S-14186, Sweden. magnus.johansson@mbb.ki.se
authors.forename: Magnus
authors.initials: M
authors.lastname: Johansson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016415:Sequence Alignment; D013936:Thymidine / Q000378:metabolism; D014018:Tissue Distribution; D014529:Uridine / Q000737:chemistry / Q000378:metabolism; D014543:Uridine Phosphorylase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D011993:Recombinant Fusion Proteins; D014543:Uridine Phosphorylase; C476698:uridine phosphorylase-2, human; D013936:Thymidine; D014529:Uridine