用一种维生素E类似物修复氨基酸基团。

Repair of amino acid radicals by a vitamin E analogue.

作者信息

Bisby R H, Ahmed S, Cundall R B

出版信息

Biochem Biophys Res Commun. 1984 Feb 29;119(1):245-51. doi: 10.1016/0006-291x(84)91644-9.

Abstract

Free radicals derived from one-electron oxidation of the amino acids tryptophan, tyrosine, methionine and histidine have been found to be rapidly (k = 10(7) -10(9) dm3 mol-1 s-1) and efficiently repaired by Trolox C, a vitamin E analogue. The reactions form a relatively stable phenoxyl radical of Trolox C (lambda max = 440 nm; epsilon = 5.4 X 10(3) mol dm-3 cm-1). The radical cation of tryptophan is more rapidly repaired than the neutral tryptophan radical. Repair of tryptophanyl radicals in the enzyme lysozyme has also been observed. The results suggest that a function of alpha-tocopherol in membranes may be the repair of radicals of integral membrane proteins.

摘要

已发现，色氨酸、酪氨酸、蛋氨酸和组氨酸经单电子氧化产生的自由基能被维生素E类似物Trolox C迅速（速率常数k = 10⁷ - 10⁹ dm³ mol⁻¹ s⁻¹）且有效地修复。这些反应形成了一种相对稳定的Trolox C苯氧自由基（最大吸收波长λmax = 440 nm；摩尔吸光系数ε = 5.4×10³ mol dm⁻³ cm⁻¹）。色氨酸的自由基阳离子比中性色氨酸自由基修复得更快。在溶菌酶中也观察到了色氨酸自由基的修复。结果表明，α-生育酚在膜中的一个功能可能是修复膜整合蛋白的自由基。