title: Pyrimidine metabolism in Trichomonas vaginalis.
abstract: Pyrimidine metabolism in Trichomonas vaginalis was investigated using washed cell suspensions of the organism with radiolabelled pyrimidine ring precursors and preformed pyrimidines. The precursors [14C]orotate, [14C]bicarbonate and [14C]aspartate were not incorporated into the pyrimidine bases of trichomonal nucleic acids, indicating that the protozoan is unable to synthesise the pyrimidine ring and is dependent on the salvage of exogenous pyrimidines. [3H]uracil, [3H]uridine, [3H]cytidine, deoxy[3H]cytidine and [3H]thymidine were all efficiently salvaged, and interconversion between cytosine and uracil nucleotides was detected. Thymidylate synthase activity was not detected, suggesting that T. vaginalis is dependent upon an exogenous supply of thymidine for TMP synthesis.
mesh_terms: D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D001639:Bicarbonates / Q000378:metabolism; D003597:Cytosine Nucleotides / Q000378:metabolism; D009963:Orotic Acid / Q000378:metabolism; D011743:Pyrimidines / Q000378:metabolism*; D013936:Thymidine / Q000378:metabolism; D013940:Thymidylate Synthase / Q000378:metabolism; D014246:Trichomonas vaginalis / Q000378:metabolism*; D014500:Uracil Nucleotides / Q000378:metabolism
chemical_list: D001639:Bicarbonates; D003597:Cytosine Nucleotides; D011743:Pyrimidines; D014500:Uracil Nucleotides; D001224:Aspartic Acid; D009963:Orotic Acid; D013940:Thymidylate Synthase; D013936:Thymidine