Cadman E, Heimer R
Cancer Res. 1986 Mar;46(3):1195-8.
The binding of 5-fluoro-2'-deoxyuridylate generated from 5-fluoro-2'-deoxyuridine in intact cells was used to measure changes in the level of thymidylate synthetase during the course of population growth of murine leukemia L 1210 cells. By the use of elutriation techniques and flow cytometric analysis, the amount and activity of thymidylate synthetase associated with the various phases of the cell cycle were determined for the L 1210 cells during unperturbed in vitro culture growth. Fluctuations of thymidylate synthetase levels were associated with the cell cycle; there was a positive correlation (P less than 0.001) between the percentage of the total cell population in S phase and the concentration of thymidylate synthetase, although there was an increase in the level of this enzyme in association with an increase in G2-M cells, this did not achieve statistical significance. A negative correlation between G1 cells and the concentration of thymidylate synthetase was also observed. The maximum amount of thymidylate synthetase was nearly 900 fmol/10(6) cells and occurred in cell populations during logarithmic growth when the percentage of the population in S phase and G2-M phase was greater than 50 and 20%, respectively. In late culture growth (plateau) when only 25% of the cell population was in S phase and nearly 75% of the population was in G1 phase, the level of enzyme was reduced to 200 fmol/10(6) cells.
利用完整细胞中由5-氟-2'-脱氧尿苷生成的5-氟-2'-脱氧尿苷酸的结合来测量鼠白血病L 1210细胞群体生长过程中胸苷酸合成酶水平的变化。通过淘洗技术和流式细胞术分析，确定了在未受干扰的体外培养生长过程中L 1210细胞与细胞周期各阶段相关的胸苷酸合成酶的量和活性。胸苷酸合成酶水平的波动与细胞周期相关；S期细胞在总细胞群体中的百分比与胸苷酸合成酶浓度之间存在正相关（P小于0.001），尽管随着G2-M期细胞增加该酶水平也增加，但这未达到统计学显著性。还观察到G1期细胞与胸苷酸合成酶浓度之间呈负相关。胸苷酸合成酶的最大量接近900 fmol/10(6)个细胞，出现在对数生长期的细胞群体中，此时S期和G2-M期细胞在群体中的百分比分别大于50%和20%。在培养后期（平台期），当只有25%的细胞群体处于S期且近75%的群体处于G1期时，酶水平降至200 fmol/10(6)个细胞。
