Chiang Y L, King T E
J Biol Chem. 1979 Mar 25;254(6):1845-53.
Cytochrome c1 forms an active complex with cytochrome c as previously reported (Chiang, Y. L., Kaminsky, L. S., and King, T. E. (1976) J. Biol. Chem. 251, 29-36). It also forms a complex with cytochrome oxidase with heme ratio of 1:1. This cytochrome c1.oxidase complex has been purified by ammonium sulfate fractionation and is stable in media of high ionic strength (greater than 0.1 M) but dissociates as the pH deviates from neutral. The purified cytochrome c1 aggregates to an oligomer, presumably a pentamer. No agent has been found to depolymerize isolated c1 without denaturation. However, in the cytochrome c1.oxidase complex, these two cytochromes apparently were depolymerized to form smaller aggregates, if not monomeric units, as judged by sedimentation behavior. Cytochrome c1 also forms a ternary complex with cytochrome c and oxidase in the heme ratio of 1:1:1. This complex can be prepared by any of the following four methods: (i) c1 + c + oxidase: (ii) c1.c complex + oxidase; (iii) c1 + c.oxidase complex: or (iv) c + c1.oxidase complex. The mode of formation of these complexes is all from pure protein-protein interactions. Cytochrome c1 is also incorporated into phospholipid vesicles and these vesicles show about 200 molecules of phospholipid/cytochrome c1 in terms of heme. The spectrophotometric, circular dichroic, sedimentation behavior and enzymic properties of these complexes have been investigated.
如先前报道，细胞色素c1与细胞色素c形成活性复合物（蒋，Y.L.，卡明斯基，L.S.，和金，T.E.（1976年）《生物化学杂志》251，29 - 36）。它还与细胞色素氧化酶形成复合物，血红素比例为1:1。这种细胞色素c1 - 氧化酶复合物已通过硫酸铵分级分离纯化，在高离子强度（大于0.1M）的介质中稳定，但随着pH偏离中性而解离。纯化的细胞色素c1聚集成寡聚体，推测为五聚体。尚未发现能使分离的c1解聚而不发生变性的试剂。然而，在细胞色素c1 - 氧化酶复合物中，根据沉降行为判断，这两种细胞色素显然解聚形成了较小的聚集体，即便不是单体单元。细胞色素c1还与细胞色素c和氧化酶形成血红素比例为1:1:1的三元复合物。这种复合物可以通过以下四种方法中的任何一种制备：（i）c1 + c + 氧化酶；（ii）c1.c复合物 + 氧化酶；（iii）c1 + c.氧化酶复合物；或（iv）c + c1.氧化酶复合物。这些复合物的形成方式均来自纯蛋白质 - 蛋白质相互作用。细胞色素c1也被整合到磷脂囊泡中，就血红素而言，这些囊泡显示每分子细胞色素c1约有200个磷脂分子。已对这些复合物的分光光度法、圆二色性、沉降行为和酶学性质进行了研究。
