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Pyrimidine 5'-nucleosidase in Neisseria meningitidis. An enzyme specific for uridine 5'-monophosphate
1Kaptein W. Wilhelmsen og Frues Bakteriologiske Institutt, University of Oslo, Rikshospitalet, Norway.
Abstract:
A previously unknown pyrimidine 5'-nucleosidase (pyrimidine 5'-nucleotide phosphoribohydrolase) specific for uridine 5'-monophosphate (5'-UMP) was present in crude extract from Neisseria meningitidis. Of seven strains, six were found to degrade the N-glycosidic linkage of 5'-UMP. One strain showed negligible activity. The substrate was quantitatively converted to uracil and ribose 5'-phosphate (R5P). Cytidine 5'-monophosphate (5'-CMP) or the 2-deoxy 5'-monophosphates of the pyrimidine nucleosides (5'-dUMP, 5'-dCMP, 5'-dTMP) were found not to be degraded. Neither was uridine 3'-monophosphate (3'-UMP) degraded by extracts from the three strains selected for this test.
Insights
Neisseria meningitidis contains a novel pyrimidine 5'-nucleosidase that specifically degrades uridine 5'-monophosphate (5'-UMP) into uracil and ribose 5'-phosphate (R5P). This enzyme activity was observed in most tested strains.
Area of Science:
- Microbiology
- Biochemistry
- Enzymology
Background:
- Pyrimidine nucleosides are essential components of nucleic acids.
- The enzymatic degradation of pyrimidine nucleotides plays a role in cellular metabolism and nutrient recycling.
- Neisseria meningitidis is a significant human pathogen, and understanding its metabolic capabilities is crucial.
Purpose of the Study:
- To identify and characterize novel enzymes involved in pyrimidine nucleotide metabolism in Neisseria meningitidis.
- To investigate the substrate specificity of a newly discovered pyrimidine 5 '-nucleosidase.
Main Methods:
- Extraction of crude enzyme preparations from Neisseria meningitidis strains.
- Assay of enzyme activity using uridine 5 '-monophosphate (5 '-UMP) as a substrate.
- Analysis of degradation products using chromatographic and spectrophotometric methods.
- Testing of various pyrimidine nucleoside monophosphates and isomers for degradation.
Main Results:
- A previously unknown pyrimidine 5 '-nucleosidase was identified in crude extracts of Neisseria meningitidis.
- Six of seven strains exhibited significant activity, degrading 5 '-UMP quantitatively to uracil and ribose 5 '-phosphate (R5P).
- The enzyme showed high specificity, with no degradation observed for cytidine 5 '-monophosphate, deoxyribonucleotides, or uridine 3 '-monophosphate.
Conclusions:
- Neisseria meningitidis possesses a specific pyrimidine 5 '-nucleosidase capable of cleaving the N-glycosidic bond of 5 '-UMP.
- This enzyme likely contributes to pyrimidine salvage pathways or nutrient acquisition in this bacterium.
- The specificity of this enzyme suggests potential applications in biochemical research or diagnostics.