Cytidine triphosphate (CTP) synthetase activity during cell cycle progression in normal and malignant T-lymphocytic cells.
The role of cytidine triphosphate (CTP) synthetase (EC 6.3.4.2.) in the pyrimidine ribonucleotide metabolism of MOLT-3 human T-ALL cell line cells and normal human T lymphocytes during the cell cycle traverse was studied. Highly pure G1-phase samples and samples enriched in S-phase cells were obtained by counterflow centrifugation. The activity of CTP synthetase in situ, measured in pulse-chase experiments, was similar in the G1-phase and S-phase MOLT-3 cells. In contrast, in S-phase T lymphocytes, an increased activity of CTP synthetase was observed compared with G1-phase T lymphocytes. Nevertheless, the MOLT-3 samples showed an increased activity of CTP synthetase in comparison with either G1-phase or S-phase enriched samples of normal T lymphocytes. Therefore, the increased activity of CTP synthetase of MOLT-3 cells is a cell cycle-independent feature, whereas among normal T lymphocytes, the increase in activity of CTP synthetase that arises after a growth stimulus is more prominent in the S-phase.
van den Berg
A A
AA
Department of Paediatrics and Clinical Chemistry, Academic Medical Centre, Amsterdam, The Netherlands.
van Lenthe
H
H
Kipp
J B
JB
de Korte
D
D
van Kuilenburg
A B
AB
van Gennip
A H
AH
D019731:Carbon-Nitrogen Ligases; D002453:Cell Cycle; D003570:Cytidine Triphosphate / Q000096:biosynthesis; D006801:Humans; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000201:enzymology*; D008025:Ligases / Q000378:metabolism*; D009711:Nucleotides / Q000378:metabolism; D013601:T-Lymphocytes / Q000201:enzymology*; D014407:Tumor Cells, Cultured / Q000201:enzymology; D014529:Uridine / Q000378:metabolism
D009711:Nucleotides; D003570:Cytidine Triphosphate; D008025:Ligases; D019731:Carbon-Nitrogen Ligases; C019951:CTP synthetase; D014529:Uridine