Little M C, Preston J F
Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida 32611.
Plant Physiol. 1985 Feb;77(2):443-9. doi: 10.1104/pp.77.2.443.
Protoplast and cell suspension cultures of Daucus carota L. were evaluated for their sensitivity toward the three amatoxin derivatives, alpha-amanitin, 6'-deoxy-alpha-amanitin, and 6'-O-methyl-alpha-amanitin using inhibition of DNA synthesis to measure cell viability. Protoplasts appeared approximately 10-fold more refractory than suspension cells and alpha-amanitin was much less effective than the other two amatoxins, even though K(i) values for isolated RNA polymerase II were similar (4-5 nanomolar). Additional studies evaluating the recoveries of all three amatoxins from cell suspension supernates indicate one basis for these differences to be the selective degradation of alpha-amanitin. A mechanism involving the activation of the hydroxyindole moiety of the alpha-amanitin is thus invoked to explain these differences and we postulate the involvement of plant oxidases in this role.
利用DNA合成抑制来测定细胞活力，对胡萝卜（Daucus carota L.）的原生质体和细胞悬浮培养物针对三种鹅膏毒素衍生物（α-鹅膏菌素、6'-脱氧-α-鹅膏菌素和6'-O-甲基-α-鹅膏菌素）的敏感性进行了评估。原生质体的耐受性似乎比悬浮细胞高约10倍，并且α-鹅膏菌素的效力远低于其他两种鹅膏毒素，尽管分离的RNA聚合酶II的K(i)值相似（4-5纳摩尔）。评估从细胞悬浮上清液中回收所有三种鹅膏毒素的进一步研究表明，这些差异的一个原因是α-鹅膏菌素的选择性降解。因此，我们提出一种涉及α-鹅膏菌素羟基吲哚部分激活的机制来解释这些差异，并推测植物氧化酶在这一过程中发挥作用。
