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Keywords:

  • aspartate transcarbamoylase;
  • biosynthesis;
  • Pseudomonas;
  • pyrimidines;
  • regulation

Abstract

Aims:  To investigate the regulation of de novo pyrimidine biosynthesis in the bacterium Pseudomonas resinovorans ATCC 14235.

Methods and Results:  The pyrimidine biosynthetic pathway enzymes were measured in cell extracts from P. resinovorans ATCC 14235 and from an auxotroph lacking orotate phosphoribosyltransferase activity. Pyrimidine biosynthetic pathway enzyme activities in ATCC 14235 were affected by the addition of pyrimidine bases to the culture medium. The de novo enzyme activities of the phosphoribosyltransferase mutant strain increased after pyrimidine starvation indicating possible repression of the pathway by a pyrimidine-related compound. Aspartate transcarbamoylase activity in ATCC 14235 was inhibited in vitro by ATP, UTP and pyrophosphate.

Conclusions:  Pyrimidine biosynthesis in P. resinovorans was regulated at the level of enzyme synthesis and at the level of activity for aspartate transcarbamoylase. Its regulation of enzyme synthesis seemed to be similar to what has been observed in the taxonomically related species Pseudomonas oleovorans.

Significance and Impact of the Study:  This study found that pyrimidine biosynthesis is regulated in P. resinovorans. This could prove helpful to future studies investigating polyhydroxyalkanoate production by the bacterium.