Pyrimidine nucleotide pool changes during the cell cycle and quiescence. Pyrimidine excretion and metabolic isolation of the pyrimidine mononucleoside polyphosphate pool
We have measured the pyrimidine nucleotide contents of the culture fluid, acid-soluble fraction, and acid-insoluble fraction of cultures of hamster embryo fibroblasts (third subculture) through the final two divisions of growth in culture. The cells show a growth delay between the penultimate and ultimate division periods and a concomitant biochemical synchrony of pyrimidine metabolism. The cells exhibit normal excretion of pyrimidine nucleosides beginning with the ultimate division cycle. This excretion results from the net breakdown of ribonucleic acid and a cell-regulated maximum for pyrimidine mononucleoside polyphosphate content. This upper limit for the pyrimidine nucleoside polyphosphate content is not a steady state phenomenon but rather an absence of both synthesis and utilization. The hamster embryo fibroblast exhibits a directed flow of salvage uridine for ribonucleic acid synthesis. We show that de novo synthetic uridine 5'-monophosphate also can be used for ribonucleic acid synthesis without prior entry into the cytoplasmic uridine nucleoside polyphosphate pool. During attachment and first division salvage uridine does enter the cytoplasmic nucleotide pool. The properties of the cytidine pools differ from the uridine pools in specific activity and levels of cytidine, due to turnover of the terminal C-C-A of cytoplasmic transfer ribonucleic acid and the delay in conversion of nonradioactive de novo synthetic uridine 5'-monophosphate to cytidine 5'-triphosphate. The partial synchrony in these cultures has been used as a temporal marker of the observed events.
- Research Organization:
- Oak Ridge National Lab., TN
- OSTI ID:
- 6721423
- Journal Information:
- J. Biol. Chem.; (United States), Vol. 255:23
- Country of Publication:
- United States
- Language:
- English
Similar Records
The pyrimidine nucleotide carrier PNC1 and mitochondrial trafficking of thymidine phosphates in cultured human cells
Pyrimidine biosynthesis in normal and transformed cells
Related Subjects
CELL CYCLE
BIOCHEMICAL REACTION KINETICS
PYRIMIDINES
METABOLISM
RNA
BIOSYNTHESIS
BIOLOGICAL PATHWAYS
CELL CULTURES
EMBRYONIC CELLS
FIBROBLASTS
ONTOGENESIS
ANIMAL CELLS
AZINES
CONNECTIVE TISSUE CELLS
HETEROCYCLIC COMPOUNDS
KINETICS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
REACTION KINETICS
SOMATIC CELLS
SYNTHESIS
550200* - Biochemistry
550300 - Cytology