Pyrimidine base and ribonucleoside catabolic enzyme activities of the Pseudomonas diminuta group

Abstract

Pyrimidine base and ribonucleoside catabolic enzyme activities of the two type strains of the Pseudomonas diminuta group were investigated for taxonomic classification purposes. The presence of the pyrimidine salvage enzyme nucleoside hydrolase was indicated in both type strains following thin-layer chromatographic analysis. The presence of the hydrolase was also confirmed by enzyme assay. In addition, the activities of the pyrimidine salvage enzymes dihydropyrimidine dehydrogenase and dihydropyrimidinase were measurable in cell-free extracts of both P. diminuta and P. vesicularis. An absence of cytosine deaminase activity was found when assaying extracts of the two type strains. Nucleoside hydrolase and dihydropyrimidine dehydrogenase levels in P. vesicularis were influenced by carbon source while dihydropyrimidinase activity was observed to increase after P. diminuta growth on dihydrothymine as a nitrogen source.

Cloning, sequencing, and expression in Escherichia coli of the D-hydantoinase gene from Pseudomonas putida and distribution of homologous genes in other microorganisms

“…Within this group, not all strains possess D-hydantoinase activity. The strains that were not induced by hydantoin were also not induced by dihydrothymine, which has been shown to induce dihydropyrimidinase activity in Pseudomonas stutzeri (43), Pseudomonas pseudoalcaligenes (40), and Pseudomonas diminuta (41). Dihydrothymine did not induce higher levels of dihydropyrimidinase activity in Pseudomonas aeruginosa (12).…”