Saheki T, Imamura Y, Inoue I, Miura S, Mori M, Ohtake A, Tatibana M, Katsumata N, Ohno T
J Inherit Metab Dis. 1984;7(1):2-8. doi: 10.1007/BF01805609.
We report an ornithine transcarbamylase(OTC)-deficient male patient who had no detectable immunoreactive materials but did have active mRNA for OTC-related protein. The total absence of OTC activity in the liver of the patient was caused by a complete lack of immunoreactive material, as determined by Ouchterlony double immunodiffusion, single radial immunodiffusion, and sodium dodecylsulphate-polyacrylamide gel electrophoresis of immunoprecipitate and of liver homogenate. However, mRNA coding for the precursor of OTC was clearly detected in autopsy specimens of the patient's liver as well as of controls in a cell-free translation system consisting of rabbit reticulocyte lysates and [35S]methionine. The labelled precursor of OTC synthesized in vitro with mRNA from the patient could be transported into rat liver and kidney mitochondria and processed to form a protein with a molecular weight indistinguishable from mature OTC, suggesting that there was no defect in the protein structure necessary for its transport into mitochondria. These results suggest that the primary defect of the OTC deficiency was located in the structural gene and that the labile OTC-related protein, after being synthesized with its mRNA, was degraded too rapidly to be detected by the method used.
我们报告了一名鸟氨酸转氨甲酰酶（OTC）缺乏的男性患者，其体内未检测到免疫反应性物质，但确实存在与OTC相关蛋白的活性mRNA。通过免疫双扩散、单向放射免疫扩散以及对免疫沉淀物和肝脏匀浆进行十二烷基硫酸钠-聚丙烯酰胺凝胶电泳检测发现，患者肝脏中完全缺乏免疫反应性物质，这导致了OTC活性完全缺失。然而，在由兔网织红细胞裂解物和[35S]甲硫氨酸组成的无细胞翻译系统中，在患者肝脏以及对照的尸检标本中均清晰检测到了编码OTC前体的mRNA。用患者的mRNA在体外合成的OTC标记前体能够转运至大鼠肝脏和肾脏线粒体中，并加工形成一种分子量与成熟OTC无法区分的蛋白质，这表明其转运至线粒体所需的蛋白质结构不存在缺陷。这些结果表明，OTC缺乏的主要缺陷位于结构基因，并且与OTC相关的不稳定蛋白在与其mRNA一起合成后，降解速度太快，以至于无法用所使用的方法检测到。
