Archives of Microbiology

, Volume 152, Issue 2, pp 115–118

Pyrimidine, purine and nitrogen control of cytosine deaminase synthesis in Escherichia coli K12. Involvement of the glnLG and purR genes in the regulation of codA expression


  • Lennart Andersen
    • Institute of Biological Chemistry BUniversity of Copenhagen
  • Mogens Kilstrup
    • Institute of Biological Chemistry BUniversity of Copenhagen
  • Jan Neuhard
    • Institute of Biological Chemistry BUniversity of Copenhagen
Original Papers

DOI: 10.1007/BF00456087

Cite this article as:
Andersen, L., Kilstrup, M. & Neuhard, J. Arch. Microbiol. (1989) 152: 115. doi:10.1007/BF00456087


Cytosine deaminase, encoded by the codA gene in Escherichia coli catalyzes the deamination of cytosine to uracil and ammonia. Regulation of codA expression was studied by determining the level of cytosine deaminase in E. coli K12 grown in various defined media. Addition of either pyrimidine or purine nucleobases to the growth medium caused repressed enzyme levels, whereas growth on a poor nitrogen source such as proline resulted in derepression of cytosine deaminase synthesis. Derepression of codA expression was induced by starvation for either uracil or cytosine nucleotides. Nitrogen control was found to be mediated by the glnLG gene products, and purine repression required a functional purR gene product. Studies with strains harbouring multiple mutations affecting both pyrimidine, purine and nitrogen control revealed that the overall regulation of cytosine deaminase synthesis by the different metabolites is cumulative.

Key words

Escherichia colicodAglnLGpurRGene regulationCytosine deaminase
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Copyright information

© Springer-Verlag 1989