MAGNETIC SPIN EFFECTS IN RADICAL ENZYMATIC REACTIONS

我们的实验室正在使用磁场来改变电子-自旋相互作用系统 化学反应和酶反应中与自由基的交叉率 中间体来证明自由基反应途径的存在。仅限 带有自旋相关自由基中间体的酶可能会受到 磁场。这些磁场可能是外生的(实验室 产生“磁场效应”的电磁铁)或内生的 (由参与成键的原子的核磁矩引起 均相溶解从而引起“磁同位素效应”)。这些 以前已经在化学系统中证明了这种效应，但我们的研究 研究小组是第一个在酶系统中研究这些效应的人 有自旋相关的自由基对中间体。 我们的实验目标是：(1)确定磁场依赖关系 自由基酶的动力学参数和同位素效应 乙醇胺解氨酶、二醇脱水酶、脂氧合酶、多巴胺-B- 羟基酶、缩氨酸酰胺化单加氧酶、苯丙氨酸 羟基酶和DNA光解酶。在初步实验中，我们有 证明了磁场与乙醇胺的比率有关 氨裂解酶、脂氧合酶和缩氨甘氨酸酰胺化单加氧酶。 (2)确定磁场对光解的影响。 维生素B-12(钴胺)共因子的激光闪光光解。 尽管我们的主要关注点是开发新的研究技术 酶与自由基中间体形成更完整的 了解磁性自旋化学在酶中的作用 未配对的电子，我们的工作也将解决一个日益增长的问题，即如何 环境磁场可能会与生物系统相互作用。

Our laboratory is using magnetic fields to alter electron-spin intersystem crossing rates in chemical and enzymatic reactions with radical intermediates to prove the existence of radical reaction pathways. Only enzymes with spin-correlated radical intermediates can be affected by a magnetic field. These magnetic fields can be exogenous (a laboratory electromagnet giving rise to a "Magnetic Field Effect") or endogenous (arising from the nuclear magnetic moment of atoms involved in bond homolysis thereby giving rise to a "Magnetic Isotope Effect"). These effects have been demonstrated in chemical systems before, but our research group is the first to study these effects in enzymatic systems postulated to have spin-correlated radical pair intermediates. Our experimental goals are: (1) To determine the magnetic field dependence of the kinetic parameters and isotope effects on the radical enzymes ethanolamine ammonia lyase, diol dehydrase, lipoxygenase, dopamine-B- hydroxylase, peptidylglycine amidating monooxygenase, phenylalanine hydroxylase, and DNA photolyase. In preliminary experiments, we have demonstrated a magnetic field dependence to the rate of ethanolamine ammonia lyase, lipoxygenase, and peptidylglycine amidating monooxygenase. (2) To determine the effect of a magnetic field on the photolysis of vitamin B-12 (cobalamin) cofactors by laser flash photolysis. Although our primary focus is to develop new techniques for studying enzymes with radical intermediates and contribute to a more complete understanding of the role of magnetic spin chemistry in the enzymes with unpaired electrons, our work will also address the growing question of how environmental magnetic fields might interact with biological systems.