Steiner D F, Cunningham D, Spigelman L, Aten B
Science. 1967 Aug 11;157(3789):697-700. doi: 10.1126/science.157.3789.697.
Human islet cell tumor tissue and isolated islets of Langerhans from rats incorporated radioactive amino acids in vitro into insulin and a larger acid-alcohol soluble protein which could be separated from insulin by gel filtration. The amino acids were incorporated into the larger protein earlier than into insulin; only after incubation of islets for approximately 30 minutes did radioactivity begin to appear in insulin. The transfer of about 70 percent of the radioactivity of the larger protein to insulin was demonstrated in the absence of new peptide bond synthesis (cycloheximide), or during incubation with unlabeled amino acid (chase). The results indicate that the larger protein is a precursor in the biosynthesis of insulin. The name "proinsulin" is suggested for this protein.
人胰岛细胞瘤组织以及从大鼠分离出的胰岛在体外能将放射性氨基酸掺入胰岛素和一种更大的酸醇溶性蛋白中，这种蛋白可通过凝胶过滤与胰岛素分离。氨基酸掺入更大的蛋白比掺入胰岛素更早；胰岛孵育约30分钟后放射性才开始出现在胰岛素中。在没有新肽键合成（环己酰亚胺）的情况下，或在与未标记氨基酸一起孵育（追踪）时，证明约70%的更大蛋白的放射性转移到了胰岛素中。结果表明，更大的蛋白是胰岛素生物合成中的前体。建议将这种蛋白命名为“胰岛素原”。
