硫自由基与氧的相互作用：脉冲辐解研究

Interactions of thiyl free radicals with oxygen: a pulse radiolysis study.

作者信息

Tamba M, Simone G, Quintiliani M

出版信息

Int J Radiat Biol Relat Stud Phys Chem Med. 1986 Oct;50(4):595-600. doi: 10.1080/09553008614550991.

Abstract

A pulse radiolysis study of glutathione in aqueous solution at pH 5.5 containing N2O/O2 mixtures at various ratios indicates that oxygen rapidly adds to the thiyl glutathione radical yielding a transient absorption, with a maximum at 540 nm, whose characteristics appear to be compatible with assignment to the GSOO. radical. The reaction (Formula: see text) appears to be an equilibrium whose kinetic constants have been estimated (kf = 2.0 X 10(9) dm3 mol-1, kb = 6.2 X 10(5) s-1). Evidence for electron transfer from ascorbate to the GSOO. radical has been obtained and the respective rate constant has been determined to be 1.75 +/- 0.15 X 10(8) dm3 mol-1 s-1.

摘要

在pH 5.5的水溶液中，对含有不同比例N₂O/O₂混合物的谷胱甘肽进行的脉冲辐解研究表明，氧气迅速加成到谷胱甘肽硫基自由基上，产生一个瞬态吸收峰，其最大吸收波长在540 nm，其特征似乎与归属于GSOO·自由基相符。该反应（公式：见原文）似乎是一个平衡反应，其动力学常数已被估算（正向速率常数kf = 2.0×10⁹ dm³ mol⁻¹，逆向速率常数kb = 6.2×10⁵ s⁻¹）。已获得抗坏血酸向GSOO·自由基电子转移的证据，且相应的速率常数已确定为1.75±0.15×10⁸ dm³ mol⁻¹ s⁻¹。