Peters E H, Nishi S, Miura K, Lorscheider F L, Dixon G H, Tamaoki T
Cancer Res. 1979 Sep;39(9):3702-6.
Murine alpha-fetoprotein was synthesized in a wheat germ cell-free system in the presence of radioactive amino acids under the direction of alpha-fetoprotein messenger RNA isolated from mouse yolk sacs. The radiolabeled alpha-fetoprotein was isolated by immunoabsorption, and the amino acid residues at the NH2 terminus were determined by radioactive sequencing techniques. In a comparison to the NH2-terminal sequence of circulating alpha-fetoprotein, the in vitro-synthesized alpha-fetoprotein was found to contain an extra peptide 20 amino acids long linked at the NH2 terminus, the sequence of which is: (formula: see text). The molecular size, the hydrophobic nature, and the other properties of the peptide are consistent with the "leader" or "signal" piece found in the precursors of many other secretory proteins. This suggests that alpha-fetoprotein, the synthesis of which is limited primarily to fetal development, is produced in the form of the precursor as are secretory proteins in the adult tissues.
在从小鼠卵黄囊中分离出的甲胎蛋白信使核糖核酸的指导下，在含有放射性氨基酸的无细胞小麦胚芽系统中合成了小鼠甲胎蛋白。通过免疫吸附分离出放射性标记的甲胎蛋白，并通过放射性测序技术确定了其氨基末端的氨基酸残基。与循环中甲胎蛋白的氨基末端序列相比，发现体外合成的甲胎蛋白在氨基末端含有一个额外的20个氨基酸长的肽段，其序列为：（分子式：见正文）。该肽段的分子大小、疏水性及其他特性与许多其他分泌蛋白前体中发现的“前导”或“信号”片段一致。这表明主要限于胎儿发育阶段合成的甲胎蛋白，是以与成年组织中分泌蛋白相同类型的前体形式产生的。
