Control of pyrimidine nucleotide formation  in Pseudomonas fulva.
Control of pyrimidine formation was examined in Pseudomonas fulva ATCC 31418. Pyrimidine supplementation lowered pyrimidine biosynthetic pathway enzyme activities in cells grown on glucose or succinate as a carbon source indicating possible repression of enzyme synthesis. Pyrimidine limitation experiments were conducted using an orotidine 50-monophosphate decarboxylase mutant strain isolated in this study. Compared to uracil-supplemented, glucose-grown mutant cells, pyrimidine limitation of this strain caused aspartate transcarbamoylase, dihydroorotase, dihydroorotate dehydrogenase and orotate phosphoribosyltransferase activities to increase about 6-, 13-, 3-, 15-fold, respectively, which confirmed regulation of enzyme synthesis by pyrimidines. At the level of enzyme activity, transcarbamoylase activity in Ps. fulva was strongly inhibited by pyrophosphate, CTP, GTP and GDP under saturating substrate concentrations.
West
Thomas P
TP
Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA. Thomas.West@sdstate.edu
D001221:Aspartate Carbamoyltransferase / Q000378:metabolism; D003570:Cytidine Triphosphate / Q000494:pharmacology; D004080:Dihydroorotase / Q000378:metabolism; D000090722:Dihydroorotate Dehydrogenase; D011756:Diphosphates / Q000494:pharmacology; D004791:Enzyme Inhibitors; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D005947:Glucose; D006153:Guanosine Diphosphate / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000494:pharmacology; D009962:Orotate Phosphoribosyltransferase / Q000378:metabolism; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000378:metabolism; D011549:Pseudomonas / Q000378:metabolism / Q000502:physiology*; D011742:Pyrimidine Nucleotides / Q000096:biosynthesis*; D014498:Uracil / Q000378:metabolism
D000090722:Dihydroorotate Dehydrogenase; D011756:Diphosphates; D004791:Enzyme Inhibitors; D011742:Pyrimidine Nucleotides; D006153:Guanosine Diphosphate; D014498:Uracil; D003570:Cytidine Triphosphate; D006160:Guanosine Triphosphate; D044925:Oxidoreductases Acting on CH-CH Group Donors; D001221:Aspartate Carbamoyltransferase; D009962:Orotate Phosphoribosyltransferase; D004080:Dihydroorotase; D005947:Glucose