Sueishi Yoshimi, Takemoto Tsubasa
Department of Chemistry, Faculty of Science, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan.
Department of Chemistry, Faculty of Science, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan.
Bioorg Med Chem Lett. 2015 Apr 15;25(8):1808-1810. doi: 10.1016/j.bmcl.2014.12.017. Epub 2014 Dec 19.
The scavenging rates of DOPA (dl- and l-3-(3,4-dihydroxyphenyl)alanine) and Tyr (tyrosine (dl- and l-3-(4-hydroxyphenyl)alanine)) against five reactive oxygen species (ROS) and methyl radical were measured with the use of electron spin resonance (ESR) spin-trapping method and the scavenging rate constants of DOPA and Tyr were determined. The scavenging rate constants for multiple active species increased in the order of O2(-)<RO<(1)O2<H3C<HO for Tyr and RO≈O2(-)<(1)O2≈H3C<HO for DOPA, and the differences in the radical scavenging abilities for l-enantiomers and dl-mixtures of DOPA and Tyr were shown. Further, based on the redox potentials, we have suggested that the primary chemical process of antioxidant reactions with O2(-) and (1)O2 can be characterized with the electron transfer of antioxidants (DOPA and Tyr).
使用电子自旋共振（ESR）自旋捕集法测量了左旋多巴（dl-和l-3-(3,4-二羟基苯基)丙氨酸）和酪氨酸（酪氨酸（dl-和l-3-(4-羟基苯基)丙氨酸））对五种活性氧（ROS）和甲基自由基的清除率，并测定了左旋多巴和酪氨酸的清除速率常数。酪氨酸对多种活性物种的清除速率常数按O2(-)<RO<(1)O2<H3C<HO的顺序增加，左旋多巴的清除速率常数顺序为RO≈O2(-)<(1)O2≈H3C<HO，并且显示了左旋多巴和酪氨酸的l-对映体与dl-混合物在自由基清除能力上的差异。此外，基于氧化还原电位，我们认为抗氧化剂（左旋多巴和酪氨酸）与O2(-)和(1)O2的抗氧化反应的主要化学过程可以通过抗氧化剂的电子转移来表征。
