EPR in Life Science

自旋标记蛋白中硝基氧化物的迁移率分析
EPR与位置定向的自旋标记（SDSL）结合使用，是研究膜蛋白结构和动力学的技术。EPR提供了有关自旋标签的本地环境的信息，该环境具有未配对电子，但当蛋白质内引入两个自旋标签时，也可以测量自旋间标签距离。

EPR characterization of paramagnetic centers in cytochrome c oxidase
所有已知蛋白的大约30％是金属蛋白。它们参与了各种重要的生物学重要过程，例如电子转移，药物代谢，疾病机制等。EPR不仅在研究金属蛋白的电子结构方面具有重要作用。例如，细胞色素C氧化酶是线粒体和许多细菌的呼吸链中的末端蛋白。低自旋血红素血红素A接受与亚基II结合的铜A（CUA）中心的电子，并将其转移到双核中心。

Detection and study of the active site of Cu,Zn-SOD
Many enzyme reactions involve one-electron oxidation steps with formation of paramagnetic transient state of the enzyme detectable by EPR. The paramagnetic center where the unpaired electron is located, is usually centered at a transition metal (metalloproteins) or is an amino acid derived radical. Detection and identification of the paramagnetic centers is important to understand the function of the enzymes. For example, in the native SOD1 enzyme, the active site contains one Cu(II) ion that gives a very characteristic EPR spectrum.

EPR光谱和双极耦合测定BIS-TEMPO
DNP偏振剂的正确浓度对于DNP实验的成功至关重要。即使在MAS转子中，也可以使用专利的跨度模块在DNP实验之前对样品进行预筛选。松弛时间对于DNP效率至关重要，因此在低温下的P1/2测量值以估计新极化剂的DNP效率是无价的。DNP测量中重要性的另一个特征是电子 - 电子偶极耦合，该偶联很容易从溶液和冷冻溶液EPR光谱中测量。

DNA-derived radicals detected upon CuCl2/H2O2 treatment
EPR spectroscopy in conjunction with spin trapping has been employed successfully to detect and identify high-molecular-weight species generated as a result of reactive oxygen species (ROS)-induced damage to biological macromolecules, such as DNAs and RNAs. The destruction or alteration of these materials is known to play a key role in a large number of cellular injuries and diseases.

定量EPR超氧化物的分析and hydroxyl radicals
Oxidative stress and damage in cells is associated with the development of cancer, Alzheimer‘s disease, atherosclerosis, autism, infections and Parkinson‘s disease. Reactive Oxygen Species (ROSs) are the main cause of oxidative stress and damage in cells, causing damage to proteins, lipids and DNA. Two leading ROS are radicals such as the superoxide radical (O₂•-) and the hydroxyl radical (HO•) as shown here in the Xanthine/Xanthine oxidase system where their generation and decomposition can be accurately followed with the EMXnano.

使用自旋探针CMH的超氧化物形成的时间过程
在血管细胞中，超氧化物的产生增加（O₂•-) has been suggested to occur in hypertension, diabetes, and heart failure. Thus the accurate detection and ability to quantify O₂•- are critically important in understanding the pathogenesis of these various cardiovascular disorders and other noncardiovascular diseases. As shown here the generation of superoxide over time can be easily monitored with the EMXnano.

Binding of nitric oxide to oxyhemoglobin detected at 100 K
Nitric Oxide (NO) is a highly reactive regulatory molecule which has many important physiological roles, such as a neurotransmitter in the central nervous system, a regulator of vasomotor tone in the cardiovascular system, and a cytotoxic mediator of the immune system. NO is a free radical and its short half-life (< 30 sec), has rendered direct measurement difficult. The instability of NO can be overcome by using a NO-trapping technique, in which a more stable complex is formed and subsequently detected by EPR. For example, the oxidation of nitric oxide (NO) to nitrate by oxyhemoglobin (oxyHb) is a fundamental reaction in NO biology and binding of NO to the heme can be characterized by EPR.