Lu W P, Poole R K, Kelly D P
Biochim Biophys Acta. 1984 Nov 26;767(2):326-34. doi: 10.1016/0005-2728(84)90203-2.
Cytochromes c-550 (acidic), c-550 (basic), c-551 and c-552.5 from Thiobacillus versutus have been highly purified and characterized. Their spectral properties at 77 K are described. Oxidation-reduction titrations of cytochromes c-550 (acidic) and c-550 (basic) showed them to exhibit Nernst values of n = 1, with single redox centres in the cytochromes, and to have midpoint redox potentials at pH 7.0 (Em,7) of 290 and 260 mV, respectively. Cytochrome c-551 contained two separately titratable redox components, each giving n = 1. The low potential centre (55% of titratable cytochrome) and the high potential centre (45%) had Em,7 values of -115 and +240 mV, respectively. Cytochrome c-552.5 also contained at least two redox centres. One (65% of titratable cytochrome) had n = 1 and Em,7 = 220 mV. The remaining 35% appeared to be a low potential component with an Em,7 possibly as low as -215 mV. the roles of these cytochromes in respiratory thiosulphate oxidation are discussed.
来自氧化亚铁硫杆菌的细胞色素c-550（酸性）、c-550（碱性）、c-551和c-552.5已被高度纯化并进行了表征。描述了它们在77K时的光谱特性。细胞色素c-550（酸性）和c-550（碱性）的氧化还原滴定表明，它们的能斯特值n = 1，细胞色素中具有单个氧化还原中心，在pH 7.0时的中点氧化还原电位（Em,7）分别为290和260 mV。细胞色素c-551包含两个可分别滴定的氧化还原成分，每个成分的n = 1。低电位中心（可滴定细胞色素的55%）和高电位中心（45%）的Em,7值分别为-115和+240 mV。细胞色素c-552.5也至少包含两个氧化还原中心。其中一个（可滴定细胞色素的65%）的n = 1，Em,7 = 220 mV。其余35%似乎是一个低电位成分，其Em,7可能低至-215 mV。讨论了这些细胞色素在呼吸性硫代硫酸盐氧化中的作用。
