Schultz R M, LaMarca M J, Wassarman P M
Proc Natl Acad Sci U S A. 1978 Sep;75(9):4160-4. doi: 10.1073/pnas.75.9.4160.
Measurements of the rates of incorporation of [35S]methionine into protein and the specific activities of endogenous free methionine pools have been used to calculate the absolute rates of protein synthesis in mouse oocytes during spontaneous meiotic maturation in vitro. Fluorodinitro[3H]benzene was used to determine the specific activity of the oocyte's free methionine pool. It was found that the absolute rate of protein synthesis decreased from 43 to 31 pg/hr per oocyte during meiotic progression from dictyate to metaphase II (meiotic maturation), while the size of the intracellular free methionine pool decreased from 61 to 35 fmol per oocyte during the same period. Comparable measurements made on ovulated mouse oocytes that had undergone meiotic maturation in vivo strongly suggest that the decrease in the absolute rate of protein synthesis observed during meiotic maturation in vitro is physiologically significant. An alternative method that depends upon differential expansion of the oocyte's endogenous methionine pool was also used to determine absolute rates of protein synthesis. The results of these experiments are in excellent agreement with those obtained by using fluorodinitro[3H]benzene, indicating that the oocyte's free methionine pool is not compartmentalized.
通过测量[35S]甲硫氨酸掺入蛋白质的速率以及内源性游离甲硫氨酸池的比活性，来计算体外自发减数分裂成熟过程中小鼠卵母细胞的蛋白质合成绝对速率。使用氟二硝基[3H]苯来测定卵母细胞游离甲硫氨酸池的比活性。结果发现，在从双线期到中期II的减数分裂进程（减数分裂成熟）中，每个卵母细胞的蛋白质合成绝对速率从43 pg/小时降至31 pg/小时，而同期细胞内游离甲硫氨酸池的大小从每个卵母细胞61 fmol降至35 fmol。对在体内经历减数分裂成熟的排卵小鼠卵母细胞进行的类似测量有力地表明，体外减数分裂成熟过程中观察到的蛋白质合成绝对速率的下降具有生理意义。还使用了另一种依赖于卵母细胞内源性甲硫氨酸池差异扩张的方法来确定蛋白质合成的绝对速率。这些实验结果与使用氟二硝基[3H]苯获得的结果非常一致，表明卵母细胞的游离甲硫氨酸池没有被分隔。
