儿茶酚和儿茶酚胺的脉冲辐解研究。II. 钛铁试剂与氧自由基的反应。
Pulse-radiolytic investigations of catechols and catecholamines. II. Reactions of Tiron with oxygen radical species.
作者信息
Bors W, Saran M, Michel C
出版信息
Biochim Biophys Acta. 1979 Feb 1;582(3):537-42. doi: 10.1016/0304-4165(79)90145-4.
Transient spectra and kinetic data of Tiron (1,2-dihydroxybenzene-3,5-disulphonic acid) are reported, obtained after pulse-radiolytic oxidation by hydroxyl radicals (.OH), superoxide anions (O-2) or a combination of both oxygen radicals. The rate constant with .OH radicals was determined at 1.0.10(9) M-1.s-1. Contrary to a previous report (Greenstock, C.L. and Miller, R.W. (1975) Biochim. Biophys. Acta 396, 11--16), the rate constant with O-2 of 1.0.10(7) M-1.s-1 is lower by one order of magnitude; also the semiquinone absorbs at 300 nm rather than at 400 nm. The ratio of the rate constants with .OH and O-2 of 100 again demonstrates that any oxidation reaction by the latter radical is unspecific due to the more efficient reaction of .OH radicals, leading to the same products with catechol compounds.
报道了钛铁试剂（1,2 - 二羟基苯 - 3,5 - 二磺酸）的瞬态光谱和动力学数据，这些数据是在通过羟基自由基（·OH）、超氧阴离子（O₂⁻）或两种氧自由基的组合进行脉冲辐射氧化后获得的。与羟基自由基反应的速率常数测定为1.0×10⁹ M⁻¹·s⁻¹。与之前的一份报告（格林斯托克，C.L.和米勒，R.W.（1975年）《生物化学与生物物理学报》396卷，第11 - 16页）相反，与超氧阴离子反应的速率常数为1.0×10⁷ M⁻¹·s⁻¹，低了一个数量级；此外，半醌在300 nm处吸收，而不是在400 nm处。羟基自由基与超氧阴离子的速率常数之比为100，这再次表明，由于羟基自由基反应更有效，后者自由基的任何氧化反应都是非特异性的，会与儿茶酚化合物生成相同的产物。
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