Takamiya K I, Nishimura M
Biochim Biophys Acta. 1975 Jul 8;396(1):93-103. doi: 10.1016/0005-2728(75)90192-9.
The effect of isooctane extraction on photooxidation of c-type cytochromes was investigated in Chromatium chromatophores. Photooxidation of cytochrome c-555 was not affected by isooctane-extraction was abolished by thorough extraction of ubiquinone-7, but the quantum yield of the cytochrome photooxidation remained unchanged until 90% of the total ubiquinone was extracted. The photooxidation of cytochrome c-552 was recovered by the addition of ubiquinone-7 but not by menaquinone. A dark incubation of sufficient length was needed for maximal quantum yield of cytochrome c-555 photooxidation in the presence of 30 mM ascorbate. It is proposed that there are two types of photosynthetic units (or associations of molecules involved in the primary redox reactions) in Chromatium chromatophores. The combinations of primary electron donor-reaction center chlorophyll-primary electron acceptor may be cytochrome c-552-P890=ubiquinone in one type and cytochrome c-555-P890-X in another.
在嗜色菌的载色体中研究了异辛烷萃取对 c 型细胞色素光氧化的影响。细胞色素 c-555 的光氧化不受异辛烷萃取的影响，但通过彻底萃取泛醌-7 可将其消除，不过在总泛醌的 90%被萃取之前，细胞色素光氧化的量子产率保持不变。细胞色素 c-552 的光氧化通过添加泛醌-7 得以恢复，但甲萘醌不能使其恢复。在 30 mM 抗坏血酸存在的情况下，需要进行足够长时间的暗孵育才能使细胞色素 c-555 光氧化的量子产率达到最大值。有人提出，嗜色菌载色体中存在两种类型的光合单位（或参与初级氧化还原反应的分子组合）。初级电子供体 - 反应中心叶绿素 - 初级电子受体的组合在一种类型中可能是细胞色素 c-552 - P890 = 泛醌，在另一种类型中可能是细胞色素 c-555 - P890 - X。
