Arnaud L, Taillandier G, Kaouadji M, Ravanel P, Tissut M
Laboratoire de Physiologie Cellulaire Végétale, Université Joseph Fourier, Grenoble, France.
Ecotoxicol Environ Saf. 1994 Jul;28(2):121-33. doi: 10.1006/eesa.1994.1040.
A series of 21 N'-phenyl-N,N-disubstituted ureas was studied for its effects on thylakoidal electron transfer, photophosphorylation, and photosynthetic O2 evolution in class A chloroplasts and leaf fragments. The concentrations of test compounds that produced 50% inhibition of PS II electron transfer and of photosynthesis in class A chloroplasts were highly correlated. Urea derivatives with a N-lipophilic substituent (three or four carbon chains) were uncouplers (i.e., neburon uncoupled by 50% at 7 microM). The efficiency of inhibition of PS II electron transfer was increased by the presence of a 3,4-disubstitution of the phenyl ring. The presence of N-lipophilic substituents was necessary for there to be an inhibitory effect, but an increase in the length of the chain lowered the activity. The best QSAR equations that described the inhibitory activity of the whole series were obtained when using 1 chi v or MR (probably representing dispersion forces) associated with parameters that described the steric hindrance at the p position of the phenyl ring (Verloop's B2(4), B4(4)) or in its neighborhood (such as the angular parameter A4). The inhibitory efficiency of the phenylurea series on wheat and spinach pieces led to the conclusion that some extrachloroplastic factors seemed to limit the accessibility of the D1-protein target.
研究了一系列21种N'-苯基-N,N-二取代脲对A类叶绿体和叶片片段中类囊体电子传递、光合磷酸化及光合放氧的影响。在A类叶绿体中，对PS II电子传递和光合作用产生50%抑制的受试化合物浓度高度相关。具有N-亲脂性取代基（三或四个碳链）的脲衍生物是解偶联剂（即，绿谷隆在7微摩尔时解偶联50%）。苯环3,4-二取代的存在提高了对PS II电子传递的抑制效率。N-亲脂性取代基的存在是产生抑制作用所必需的，但链长的增加会降低活性。当使用与描述苯环p位（Verloop的B2(4)、B4(4)）或其附近（如角参数A4）空间位阻的参数相关的1个chi v或MR（可能代表色散力）时，可得到描述整个系列抑制活性的最佳QSAR方程。苯基脲系列对小麦和菠菜叶片的抑制效率得出结论，一些叶绿体外部因素似乎限制了D1蛋白靶点的可及性。
