Role of cytosine deaminase and β-alanine-pyruvate transaminase in pyrimidine base catabolism by Burkholderia cepacia

• Published in: Antonie van Leeuwenhoek 2000, Vol.77 (1), p.1-5
• Main Author: West, Thomas P
• Format: Article
• Language: English
• Subjects: Bacteriology; beta-Alanine-Pyruvate Transaminase; Biological and medical sciences; Burkholderia cepacia; Burkholderia cepacia - enzymology; Burkholderia cepacia - growth & development; Burkholderia cepacia - metabolism; carbon; cell growth; Culture Media; Cytosine Deaminase; enzyme activity; Fundamental and applied biological sciences. Psychology; glucose; metabolism; metabolites; Microbiology; nitrogen; Nucleoside Deaminases - metabolism; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; pathogens; Pyrimidines - metabolism; thymine; Transaminases - metabolism; uracil
• ISSN: 0003-6072; 1572-9699
• DOI: 10.1023/A:1002062202282

A determination of the possible role of the salvage enzyme cytosine deaminase or β-alanine-pyruvate transaminase in the catabolism of the pyrimidine bases uracil and thymine by the opportunistic pathogen Burkholderia cepacia ATCC 25416 was undertaken. It was of interest to learn whether these enzymes were influenced by cell growth on pyrimidine bases and their respective catabolic products to the same degree as the pyrimidine reductive catabolic enzymes were. It was found that cytosine deaminase activity was influenced very little by cell growth on the pyrimidines tested. Using glucose as the carbon source, only B. cepacia growth on 5-methylcytosine as a nitrogen source increased deaminase activity by about three-fold relative to (NH₄)₂SO₄-grown cells. In contrast, the activity of β–alanine-pyruvate transaminase was observed to be at least double in glucose-grown ATCC 25416 cells when pyrimidine bases and catabolic products served as nitrogen sources instead of (NH₄)₂SO₄. Transaminase activity in the B. cepacia glucose-grown cells was maximal after the strain was grown on either uracil or 5-methylcytosine as a nitrogen source compared to (NH₄)₂SO₄-grown cells. A possible role for β-alanine-pyruvate transaminase in pyrimidine base catabolism by B. cepacia would seem to be suggested from the similarity in how its enzyme activity responded to cell growth on pyrimidine bases and catabolic products when compared to the response of the three reductive catabolic enzymes.