Graan T, Ort D R
Arch Biochem Biophys. 1986 Aug 1;248(2):445-51. doi: 10.1016/0003-9861(86)90497-2.
The binding of 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB) to chloroplast thylakoid membranes was investigated by analyzing the inhibition of electron transfer by DBMIB according to a steady-state rate relationship for enzyme-catalyzed reactions in the presence of tightly binding reversible inhibitors. DBMIB interacts with the cytochrome b6f complex in a manner best described by an apparent dissociation constant near 6 nM. The binding site titer is 1 mmol X mol chlorophyll-1. This number of DBMIB binding sites approaches one-half the number of cytochrome b6f complexes present in the membrane. These data suggest that the cytochrome b6f complex may function in electron transfer as a dimer, plastoquinol oxidation being totally inhibited by the binding of a single DBMIB molecule to the dimer.
通过根据存在紧密结合可逆抑制剂时酶催化反应的稳态速率关系分析2,5 - 二溴 - 3 - 甲基 - 6 - 异丙基 - 对苯醌（DBMIB）对电子转移的抑制作用，研究了DBMIB与叶绿体类囊体膜的结合。DBMIB与细胞色素b6f复合物相互作用，其表观解离常数接近6 nM，这是描述这种相互作用的最佳方式。结合位点滴定值为1 mmol·mol叶绿素-1。DBMIB结合位点的数量接近膜中存在的细胞色素b6f复合物数量的一半。这些数据表明，细胞色素b6f复合物在电子转移中可能以二聚体形式发挥作用，单个DBMIB分子与二聚体结合会完全抑制质体醌醇氧化。
