title: Regulation of pyrimidine nucleotide formation in Pseudomonas reptilivora.
abstract: OBJECTIVE
  To study the regulation of de novo pyrimidine biosynthesis in the pathogenic bacterium Pseudomonas reptilivora ATCC 14836.
  
  
  RESULTS
  The pyrimidine biosynthetic pathway enzymes were assayed in extracts of Ps. reptilivora ATCC 14836 cells and of cells from an auxotroph lacking aspartate transcarbamoylase activity. Pyrimidine biosynthetic pathway enzyme activities in ATCC 14836 were influenced by the addition of pyrimidine bases to the culture medium with orotic acid addition inducing dihydroorotase activity. Pyrimidine starvation of the transcarbamoylase mutant strain increased its de novo enzyme activities suggesting that the de novo pathway was also subject to repression by a pyrimidine-related compound. Aspartate transcarbamoylase activity in ATCC 14836 was inhibited in vitro by pyrophosphate and ATP.
  
  
  CONCLUSIONS
  Regulation of pyrimidine biosynthesis in Ps. reptilivora was observed at the level of enzyme synthesis and at the level of activity for aspartate transcarbamoylase. Its regulation of enzyme synthesis seemed to be more highly controlled than what was observed in the related species Ps. fluorescens.
  
  
  CONCLUSIONS
  This investigation found that pyrimidine biosynthesis is controlled in Ps. reptilivora. This could prove helpful to future studies exploring its pathogenicity.
authors.affiliation: Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD, USA. thomas_west@sdstate.edu
authors.forename: T P
authors.initials: TP
authors.lastname: West
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001221:Aspartate Carbamoyltransferase / Q000235:genetics / Q000378:metabolism; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D004080:Dihydroorotase / Q000235:genetics / Q000502:physiology; D000090722:Dihydroorotate Dehydrogenase; D011756:Diphosphates / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000378:metabolism; D005786:Gene Expression Regulation; D015964:Gene Expression Regulation, Bacterial; D009962:Orotate Phosphoribosyltransferase / Q000235:genetics / Q000378:metabolism; D009963:Orotic Acid / Q000378:metabolism; D009964:Orotidine-5'-Phosphate Decarboxylase / Q000235:genetics / Q000378:metabolism; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000235:genetics / Q000378:metabolism; D011549:Pseudomonas / Q000235:genetics* / Q000378:metabolism*; D011742:Pyrimidine Nucleotides / Q000378:metabolism*; D014498:Uracil / Q000378:metabolism; D014542:Uridine Monophosphate / Q000378:metabolism
chemical_list: D000090722:Dihydroorotate Dehydrogenase; D011756:Diphosphates; D004791:Enzyme Inhibitors; D011742:Pyrimidine Nucleotides; D001224:Aspartic Acid; D014498:Uracil; D009963:Orotic Acid; D000255:Adenosine Triphosphate; D014542:Uridine Monophosphate; D044925:Oxidoreductases Acting on CH-CH Group Donors; D001221:Aspartate Carbamoyltransferase; D009962:Orotate Phosphoribosyltransferase; D004080:Dihydroorotase; D009964:Orotidine-5'-Phosphate Decarboxylase; C006893:ureidosuccinic acid