半氧化色氨酸与超氧阴离子自由基的扩散控制反应。

The diffusion-controlled reaction of semioxidized tryptophan with the superoxide radical anion.

作者信息

Santus R, Patterson L K, Bazin M

机构信息

Laboratoire de Physico-Chimie de l'Adaptation Biologique, INSERM U 312, Muséum National d'Histoire Naturelle, Paris, France.

出版信息

Free Radic Biol Med. 1995 Dec;19(6):837-42. doi: 10.1016/0891-5849(95)00055-3.

DOI:10.1016/0891-5849(95)00055-3

PMID:8582656

Abstract

From pulse radiolysis measurements in oxygenated aqueous solution, the semioxidized tryptophan radical (Trp.- formed by the one-electron oxidation of Trp by Br2- radical--has been shown to oxidize the superoxide radical anion with a rate constant of k = 2 x 10(9) M-1 s-1. Proof of this reaction is found in addition of superoxide dismutase (SOD) to the system, which totally eliminates the contribution of the Trp. + O2- mechanism to Trp. decay. Little, if any, reaction of molecular oxygen with Trp. may be observed on the time scale of the pulse radiolysis experiment.

摘要

通过对含氧水溶液进行脉冲辐解测量，已表明半氧化色氨酸自由基（由Br2-自由基对色氨酸进行单电子氧化形成的Trp·）能以速率常数k = 2×10⁹ M⁻¹ s⁻¹氧化超氧阴离子自由基。在体系中加入超氧化物歧化酶（SOD）可证明该反应，这完全消除了Trp· + O2-机制对Trp·衰减的贡献。在脉冲辐解实验的时间尺度上，几乎观察不到分子氧与Trp·的反应。