Creutz C, Sutin N
Proc Natl Acad Sci U S A. 1973 Jun;70(6):1701-3. doi: 10.1073/pnas.70.6.1701.
The kinetics of the reduction of horseheart ferricytochrome c by sodium dithionite (phosphate buffer-sodium chloride; pH 6.5, mu = 1.0, 25 degrees ) features two reaction pathways; one with the rate constant k(3) = 1.17 x 10(4) M(-1) sec(-1), the other with the rate constant k(1)k(2)/k(-1) = 6.0 x 10(4) M(-1) sec(-1). These pathways are interpreted in terms of remote attack (possibly by way of the exposed edge of the porphyrin system) and adjacent attack (requiring the opening of the heme crevice). The limiting rate for the adjacent pathway (k(1) = 30 sec(-1)) is in good agreement with the rate of heme-crevice opening of ferricytochrome c determined in other studies. The implication of the adjacent attack pathway to the function of cytochrome c in vivo is discussed.
连二亚硫酸钠还原马心铁细胞色素c的动力学(磷酸盐缓冲液 - 氯化钠;pH 6.5,离子强度μ = 1.0,25℃)具有两条反应途径;一条的速率常数k(3) = 1.17 x 10⁴ M⁻¹ s⁻¹,另一条的速率常数k(1)k(2)/k(-1) = 6.0 x 10⁴ M⁻¹ s⁻¹。这些途径可通过远程攻击(可能通过卟啉系统暴露的边缘)和相邻攻击(需要血红素裂隙打开)来解释。相邻途径的极限速率(k(1) = 30 s⁻¹)与其他研究中测定的铁细胞色素c血红素裂隙打开速率高度一致。文中讨论了相邻攻击途径对细胞色素c在体内功能的影响。