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机体通过有控制的氧化从还原碳化合物取得能量,分子氧是理想的末端电子接受体.它有接受电子的倾向,可提供必要的“拉力”产生耦合反应,从而贮存能量.但由于其电子分布的不寻常,分子氧参与自发性氧化反应并不活跃.分子氧具有两个不成对的电子,是二价基物质.在进行二价或四价氧化反应前,二个电子中的一个,必须先发生自旋逆转,自旋限制会造成对氧自发反应的动力障碍,但也使氧更适合于被酶还原,底物并列结合在酶的活性部位时,有充裕时间进行反向旋转,但在游离液中,则时间远远不够.在正常氧化情况下,98%的氧还原是通过线粒体中的细胞色素aa_3复合物催化的,这种酶使氧分子发
Molecular oxygen is the ideal terminal electron acceptor because it takes energy from a reduced carbon compound through controlled oxidation. It has a propensity for accepting electrons and provides the necessary “pull” to create a coupled reaction to store energy, but because of its Unusual distribution of electrons, molecular oxygen involved in spontaneous oxidation reaction is not active.Molecular oxygen has two unpaired electrons, is a divalent base material in the divalent or tetravalent oxidation reaction, one of the two electrons , A spin-reversal must first occur, spin-limiting can cause a kinetic disorder that spontaneously reacts with oxygen, but also makes oxygen more suitable for enzymatic reduction, with sufficient time for counter-rotation when substrates are side-by-side bound to the active site of the enzyme , But in free fluid, the time is far from enough.Under normal oxidation conditions, 98% of the oxygen reduction is catalyzed by the cytochrome aa_3 complex in the mitochondria, which oxidizes oxygen molecules