Mitchell R, Mitchell P, Rich P R
Glynn Research Institute, Bodmin, UK.
FEBS Lett. 1991 Mar 25;280(2):321-4. doi: 10.1016/0014-5793(91)80321-s.
The spectral characteristics of the '655 nm' band of cytochrome oxidase were found to be affected by ligands of the binuclear centre, including formate and chloride, and by the resting/pulsed transition. The band titrated with near n = 1 characteristics at a midpoint of about 400 mV, in contrast to haem a3, which exhibits strong redox interaction and a titration range at significantly lower potential. Thus, although the total reduced-oxidised difference spectrum of haem a3 shows a trough at about 655 nm, this characteristic is absent in the low potential region. The 655 nm feature may arise from a charge transfer band of ferric high-spin haem a3, which is modulated by the redox state of CuB, as suggested by Beinert et al. [(1976) Biochim. Biophys. Acta 423, 339-355].
细胞色素氧化酶“655 nm”波段的光谱特征被发现受到双核中心配体（包括甲酸根和氯离子）以及静息/脉冲转变的影响。该波段在约400 mV的中点处呈现出接近n = 1的滴定特征，这与具有强氧化还原相互作用且滴定范围处于显著更低电位的血红素a3形成对比。因此，尽管血红素a3的总还原-氧化差光谱在约655 nm处显示出一个低谷，但在低电位区域不存在这一特征。如贝纳特等人[（1976年）《生物化学与生物物理学报》423卷，339 - 355页]所提出的，655 nm特征可能源于高铁高自旋血红素a3的电荷转移带，它受CuB氧化还原状态的调制。
