Wieland T, Götzendörfer C, Zanotti G, Vaisius A C
Eur J Biochem. 1981 Jun;117(1):161-4. doi: 10.1111/j.1432-1033.1981.tb06315.x.
The inhibition constants (Ki) of DNA-dependent RNA polymerase B (or II) from calf thymus were measured for eight synthetically obtained bicyclic amanitin-like thioethers, two R-sulfoxides, and two S-sulfoxides. These Ki values were compared with those of alpha-amanitin, its 6'-O-methylether Ia (an R-sulfoxide), the S-sulfoxide, the sulfone, the S-deoxo derivative (Id) of Ia, and several previously described amatoxins. The necessity of a beta-methyl side chain in position 3 and a hydroxy group in proline-2 was confirmed. Additionally, the presence of an isoleucine side chain in position 6 and the absence of a side chain in position 5 was recognized as important for binding to the enzyme. In the three sulfoxide samples examined, the R-diastereomer was found to be a stronger inhibitor than the S-form. The contribution of every structural element to biological activity has been discussed.
测定了从牛胸腺中提取的依赖DNA的RNA聚合酶B（或II）对8种合成的双环鹅膏毒肽样硫醚、2种R-亚砜和2种S-亚砜的抑制常数（Ki）。将这些Ki值与α-鹅膏毒肽、其6'-O-甲基醚Ia（一种R-亚砜）、S-亚砜、砜、Ia的S-脱氧衍生物（Id）以及几种先前描述的鹅膏毒素的Ki值进行了比较。证实了3位β-甲基侧链和脯氨酸-2位羟基的必要性。此外，6位异亮氨酸侧链的存在以及5位侧链的缺失被认为对与该酶的结合很重要。在所检测的3个亚砜样品中，发现R-非对映体是比S-形式更强的抑制剂。讨论了每个结构元件对生物活性的贡献。
