Evans G A, Hucko J, Rosenfeld M G
Endocrinology. 1977 Dec;101(6):1807-14. doi: 10.1210/endo-101-6-1807.
mRNA isolated from a line of functional rat pituitary tumor cells (GH3) added to a cell-free protein synthesizing system derived from wheat embryo directed the biosynthesis of only one protein which is immunoprecipitated by prolactin antiserum. This protein, 2000--3,000 daltons heavier than prolactin and referred to as preprolactin, appeared to represent the initial, authentic product of translation since [35S]methionine donated by initiator Met-tRNAi was documented to be incorporated into the N-terminal portion; the molar ratio of leucine: initiator methionine was estimated to be 25--28:1, while prolactin contains 22 leucine residues. The mRNA coding for preprolactin was demonstrated to migrate at approximately 12--13S using rate zonal centrifugation. These data are compatible with the postulate that preprolactin represents the intact, initial product of prolactin mRNA translation.
从功能性大鼠垂体肿瘤细胞系（GH3）分离得到的mRNA，加入到从小麦胚中提取的无细胞蛋白质合成系统中，仅指导一种能被催乳素抗血清免疫沉淀的蛋白质的生物合成。这种蛋白质比催乳素重2000 - 3000道尔顿，被称为前催乳素，似乎代表翻译的初始真实产物，因为起始甲硫氨酸-tRNAi提供的[35S]甲硫氨酸被证明掺入了N端部分；亮氨酸与起始甲硫氨酸的摩尔比估计为25 - 28:1，而催乳素含有22个亮氨酸残基。使用速率区带离心法证明，编码前催乳素的mRNA在约12 - 13S处迁移。这些数据与前催乳素代表催乳素mRNA翻译的完整初始产物这一假设相符。
