Gill D M, Pappenheimer A M, Brown R, Kurnick J T
J Exp Med. 1969 Jan 1;129(1):1-21. doi: 10.1084/jem.129.1.1.
When diphtheria toxin and NAD are added to soluble fractions containing aminoacyl transfer enzymes isolated from rabbit reticulocytes or from HeLa cells, free nicotinamide is released and, simultaneously, an inactive ADP ribose derivative of transferase II is formed. The reaction is reversible, and in the presence of excess nicotinamide, toxin catalyzes the restoration of aminoacyl transfer activity in intoxicated preparations. In living cultures of HeLa cells, the internal NAD concentration is sufficiently high to account for the rapid conversion, catalyzed by a few toxin molecules located in the cell membrane, of the entire cell content of free transferase II to its inactive ADP ribose derivative. Completely inactive ammonium sulfate fractions containing soluble proteins isolated from cells that have been exposed for several hours to excess toxin, can be reactivated to full aminoacyl transfer activity by addition of nicotinamide together with diphtheria toxin. Transferase II appears to be a highly specific substrate for the toxin-stimulated splitting of NAD and thus far no other protein acceptor for the ADP ribose moiety has been found.
当将白喉毒素和烟酰胺腺嘌呤二核苷酸（NAD）添加到含有从兔网织红细胞或HeLa细胞中分离出的氨酰基转移酶的可溶性组分中时，会释放出游离的烟酰胺，同时会形成转移酶II的无活性ADP核糖衍生物。该反应是可逆的，并且在过量烟酰胺存在的情况下，毒素会催化中毒制剂中氨酰基转移活性的恢复。在HeLa细胞的活培养物中，细胞内NAD浓度足够高，足以解释由位于细胞膜中的少数毒素分子催化的，将游离转移酶II的整个细胞内容物快速转化为其无活性ADP核糖衍生物的过程。从已暴露于过量毒素数小时的细胞中分离出的含有可溶性蛋白质的完全无活性的硫酸铵组分，可以通过添加烟酰胺和白喉毒素而重新激活至完全的氨酰基转移活性。转移酶II似乎是毒素刺激的NAD裂解的高度特异性底物，到目前为止尚未发现ADP核糖部分的其他蛋白质受体。
