Pyrimidine ribonucleoside catabolic enzyme activities of Pseudomonas pickettii

Pyrimidine ribonucleoside catabolic enzyme activities of the opportunistic pathogen Pseudomonas pickettii were examined. Of the pyrimidine and related compounds tested, only dihydrouracil (nitrogen source) and ribose (carbon source) supported growth. Thin-layer chromatographic separation of the urid...

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Bibliographic Details
Published in:Antonie van Leeuwenhoek 1994-01, Vol.66 (4), p.307-312
Main Author: WEST, T. P
Format: Article
Language:English
Subjects:
Amidohydrolases - metabolism
Bacteriology
Biological and medical sciences
Catalysis
Cytosine Deaminase
Dihydrouracil Dehydrogenase (NADP)
Fundamental and applied biological sciences. Psychology
Hydrolases - metabolism
Metabolism. Enzymes
Microbiology
Nucleoside Deaminases - metabolism
Oxidoreductases - metabolism
Pseudomonas - classification
Pseudomonas - enzymology
Pseudomonas - metabolism
Pseudomonas pickettii
Pyrimidines - metabolism
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Summary:Pyrimidine ribonucleoside catabolic enzyme activities of the opportunistic pathogen Pseudomonas pickettii were examined. Of the pyrimidine and related compounds tested, only dihydrouracil (nitrogen source) and ribose (carbon source) supported growth. Thin-layer chromatographic separation of the uridine and cytidine catabolities produced by P. pickettii extracts indicated that this pseudomonad contained nucleoside hydrolase activity. Its presence was confirmed by enzyme assay. Hydrolase activity was elevated in both glucose- and ribose-grown cells relative to succinate-grown cells. Nucleoside hydrolase activity was depressed when dihydrouracil served as a nitrogen source. Cytosine deaminase activity was present in extracts prepared from succinate-, glucose- or ribose-grown cells when (NH4)2SO4 served as the nitrogen source although cells grown on glucose or ribose exhibited a higher enzyme activity. Cytosine deaminase activity was not detected in extracts prepared from cells grown on dihydrouracil as a nitrogen source. Both dihydropyrimidine dehydrogenase and dihydropyrimidinase activities were measurable in P. pickettii. The dehydrogenase activity was higher with NADH than with NADPH as its nicotinamide cofactor when uracil served as its substrate. Carbon source did not affect dehydrogenase or dihydropyrimidinase activity greatly but both activities were diminished in cells grown on the nitrogen source dihydrouracil.
ISSN:0003-6072
1572-9699
DOI:10.1007/BF00882765