Studies of radicals formed by oxidative damage and by electrons

化学基团是含有未配对电子的物种。当原子之间的键被打破时，或者当电子从中性分子中移除或添加到中性分子中时，它们可以形成。自由基活性很强，在工业和生物过程中经常催化其他分子的反应。这项建议是为了更好地了解他们的行为和反应能力。我们专注于两种自由基：(A)存在于活细胞中的多肽自由基，以及(B)由电子与分子簇相加而形成的自由基。它们有有益的影响，但也会造成氧化损伤，必须控制它们的浓度。含硫分子谷胱甘肽(GSH)是造成这种现象的部分原因。它是通过放弃一个氢原子而成为一个自由基来做到这一点的。这项建议的一个方面是检查影响这一控制过程效率的GSH的化学性质。此外，我们还希望研究含硫自由基与蛋白质反应的速度，因为这种过程发生在某些酶中。电子和团簇：电子与中性分子的结合在大气、绝缘材料、气体放电、等离子体和辐照系统的化学中具有实际重要性。这项提议的一部分涉及极地地区宇宙射线形成的电子。这些物质可能会附着在平流层冰云中的分子上，并产生能破坏臭氧的自由基。这种可能性正在与魁北克舍布鲁克的其他科学家合作进行研究。和德国的于利希。其他工作涉及电子与中性分子簇的结合，以及当电子存在时团簇如何改变形状。形状将通过使用WestGrid计算机网络和我们自己的较小网络的计算机建模来确定。持有电子的强度将由美国约翰·霍普金斯大学的合作者测量。

Chemical radicals are species containing unpaired electrons. They can be formed when bonds between atoms are broken or when electrons are removed from or added to a neutral molecule. Radicals are very reactive and often catalyse reactions of other molecules in industrial and biological processes. This proposal is concerned with obtaining a better understanding of their behaviour and reactivity. We concentrate on radicals of two kinds: (a) radicals of peptides, which occur in living cells, and (b) radicals formed by the addition of electrons to clusters of molecules.   Radicals occurring in cells: Many kinds of radical occur in living cells. They have beneficial effects but also cause oxidative damage, and their concentrations must be controlled. The sulfur containing molecule glutathione (GSH) is partly responsible for this. It does so by giving up a hydrogen atom and itself becoming a radical, GS. One aspect of this proposal is to examine the chemical properties of GSH which affect the efficiency of this control process. In addition we wish to examine the rate at which a sulfur containing radical can react with a protein, since processes of this kind occur in some enzymes. Electrons and Clusters: The attachment of electrons to neutral molecules is of practical importance in the chemistry of the atmosphere, insulating materials, gas discharges, plasmas and irradiated systems. One part of this proposal is concerned with electrons formed by cosmic rays in the Polar Regions. It is possible that these may attach to molecules in stratospheric ice clouds and create radicals which can destroy ozone. This possibility is being examined in collaboration with other scientists at Sherbrooke, Que. and Jülich, Germany. Other work is concerned with the binding of electrons to clusters of neutral molecules, and how the clusters change shape when the electron is present. Shapes will be determined by computer modeling using the Westgrid computer network and our own smaller network. The strength with which electrons are held will be measured by collaborators at Johns Hopkins in the USA.