Department of Biochemistry, Oklahoma State University, Stillwater, Oklahoma 74074.
Plant Physiol. 1979 Feb;63(2):354-8. doi: 10.1104/pp.63.2.354.
The messenger ribonucleic acid fraction isolated from a protein bodyenriched fraction of developing corn (Zea mays L.) endosperm stimulated the incorporation of radioactive amino acids into at least five polypeptides when added to a wheat germ extract capable of protein synthesis. Of these, the two major polypeptides formed with messenger from freshly frozen corn were identified as precursors to zein A and B, the two major polypeptides of the prolamine fraction of corn meal (21,600 and 19,600 molecular weight). The identification was based on the relative incorporations of radioactive leucine, lysine, and methionine, and the susceptibility of the zein A precursor, but not the zein B precursor to cleavage with cyanogen bromide. Using extracts from stored frozen corn, a third polypeptide of 14,500 molecular weight was identified as a major in vitro product. It was preferentially labeled with methionine and slightly larger than a similar peptide in the zein fraction of corn meal. Two other polypeptides of still lower molecular weight could be detected above the background of probably incomplete polypeptides.
从富含玉米（Zea mays L.）胚乳蛋白体的部分中分离出的信使核糖核酸片段，添加到能够进行蛋白质合成的小麦胚提取液中后，可刺激至少五种多肽的放射性氨基酸掺入。其中，与新鲜冷冻玉米的信使形成的两种主要多肽被鉴定为醇溶蛋白 A 和 B 的前体，醇溶蛋白是玉米粉中主要的脯氨酸部分的两种主要多肽（分子量分别为 21600 和 19600）。鉴定是基于放射性亮氨酸、赖氨酸和蛋氨酸的相对掺入量，以及醇溶蛋白 A 前体而不是醇溶蛋白 B 前体对氰化溴的裂解敏感性。使用来自储存的冷冻玉米的提取物，鉴定出分子量为 14500 的第三种多肽为主要的体外产物。它优先被蛋氨酸标记，并且比玉米粉中醇溶蛋白部分中的类似肽稍大。在可能不完全的多肽的背景之上，还可以检测到另外两种分子量更低的多肽。
