Department of Life Sciences, Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030, Belgrade, Serbia.
The Vinča Institute of Nuclear Sciences, University of Belgrade, POB 522, 11001, Belgrade, Serbia.
Sci Rep. 2018 Feb 23;8(1):3530. doi: 10.1038/s41598-018-21940-7.
Coordinate and redox interactions of epinephrine (Epi) with iron at physiological pH are essential for understanding two very different phenomena - the detrimental effects of chronic stress on the cardiovascular system and the cross-linking of catecholamine-rich biopolymers and frameworks. Here we show that Epi and Fe form stable high-spin complexes in the 1:1 or 3:1 stoichiometry, depending on the Epi/Fe concentration ratio (low or high). Oxygen atoms on the catechol ring represent the sites of coordinate bond formation within physiologically relevant bidentate 1:1 complex. Redox properties of Epi are slightly impacted by Fe. On the other hand, Epi and Fe form a complex that acts as a strong reducing agent, which leads to the production of hydrogen peroxide via O reduction, and to a facilitated formation of the Epi-Fe complexes. Epi is not oxidized in this process, i.e. Fe is not an electron shuttle, but the electron donor. Epi-catalyzed oxidation of Fe represents a plausible chemical basis of stress-related damage to heart cells. In addition, our results support the previous findings on the interactions of catecholamine moieties in polymers with iron and provide a novel strategy for improving the efficiency of cross-linking.
肾上腺素（Epi）与铁在生理 pH 下的配位和氧化还原相互作用对于理解两种截然不同的现象至关重要——慢性应激对心血管系统的有害影响和富含儿茶酚胺的生物聚合物和框架的交联。在这里，我们表明 Epi 和 Fe 可以形成稳定的高自旋配合物，其化学计量比为 1:1 或 3:1，具体取决于 Epi/Fe 浓度比（低或高）。儿茶酚环上的氧原子代表生理相关的双齿 1:1 配合物中配位键形成的位点。Fe 对 Epi 的氧化还原性质略有影响。另一方面，Epi 和 Fe 形成一种复合物，作为一种强还原剂，通过 O 还原产生过氧化氢，并促进 Epi-Fe 配合物的形成。在这个过程中，Epi 不会被氧化，即 Fe 不是电子穿梭体，而是电子供体。Epi 催化的 Fe 氧化代表了与应激相关的心肌细胞损伤的合理化学基础。此外，我们的结果支持了先前关于聚合物中儿茶酚胺部分与铁相互作用的发现，并为提高交联效率提供了一种新策略。
