Pyrimidine biosynthesis in Pseudomonas oleovorans.
OBJECTIVE
To investigate the regulation of de novo pyrimidine biosynthesis in the polyhydroxyalkanoate-producing bacterium Pseudomonas oleovorans at the level of enzyme synthesis and at the level of aspartate transcarbamoylase activity.


RESULTS
The effect of pyrimidine supplementation on the pyrimidine biosynthetic pathway enzyme activities was analysed relative to carbon source. Two uracil auxotrophs of P. oleovorans were isolated that were deficient for aspartate transcarbamoylase or dihydroorotase activity. Pyrimidine limitation of these auxotrophs increased the de novo pathway activities to varying degrees depending on the pathway mutation and the carbon source utilized. At the level of aspartate transcarbamoylase activity, pyrophosphate and uridine ribonucleotides were found to be strongly inhibitory of the Ps. oleovorans enzyme.


CONCLUSIONS
Pyrimidine biosynthesis is regulated in Ps. oleovorans. Taxonomically, the regulation of the pyrimidine biosynthetic pathway appeared dissimilar from previously studied Pseudomonas species.


CONCLUSIONS
New insights regarding the regulation of nucleic acid metabolism are provided that could prove significant during the genetic manipulation of Ps. oleovorans to increase the synthesis of polyhydroxyalkanoates.
Haugaard
L E
LE
Olson Biochemistry Laboratories, Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD 57007, USA.
West
T P
TP
D001221:Aspartate Carbamoyltransferase / Q000235:genetics / Q000378:metabolism; D003470:Culture Media; D004080:Dihydroorotase / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D005947:Glucose / Q000378:metabolism; D011091:Polyesters / Q000378:metabolism; D011549:Pseudomonas / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D011743:Pyrimidines / Q000096:biosynthesis*; D019802:Succinic Acid / Q000378:metabolism
D003470:Culture Media; D011091:Polyesters; D011743:Pyrimidines; D019802:Succinic Acid; D001221:Aspartate Carbamoyltransferase; D004080:Dihydroorotase; D005947:Glucose; C030986:pyrimidine