生物氧化“逐步释能”的作用机制

The active mechanism of gradually energesis of biological oxidation

生物体内能量物质的氧化供能不同于体外的燃烧作用——O与C和H直接氧化、瞬间燃烧,释放出大量的能量。能量物质的生物氧化是在适应生物体温度和生理条件下逐步释放出能量,并且将其一部分能量通过氧化磷酸化合成ATP储存为化学能。能量物质生物氧化"逐步释能"的分子机制主要有两种形式:一是呼吸链机制,能量物质的H原子被氧化分解脱下(生成NADH或FADH2)进入呼吸链,所携带的能量沿着呼吸链逐步释放出来,偶联氧化磷酸化合成ATP;二是"加H_2O以H换C"机制,对能量物质或其氧化分解的中间体上的C原子加H_2O,H_2O分子的O原子被能量物质的C原子以有机酸氧化脱羧形成CO_2释放,H_2O分子的H原子由脱氢酶以NADH或FADH2形式脱下进入呼吸链,因此,C原子携带的能量转移到H原子,进入呼吸链逐步氧化释放出来。

The biological oxidation of nutrient substance in the organism differs in its external combustion,which C atoms and H atoms directly are oxidized with O atoms in a moment and release a lot of energy.The biological oxidation of nutrient substance in organism gradually releases off energy and stores a portion of energy as ATP through oxidative phosphorylation in appropriate temperature and physiological conditions.There are mainly two forms in the mechanism of gradually energesis of biological oxidation:one being the respiratory chain,which H atoms in nutrient substance are decomposed off with NADH or FADH 2 for entering into the respiratory chain and its energy gradually being released off along the respiratory chain coupling with the synthesis of ATP through oxidative phosphorylation;the other being add H 2 O to change C with H,which H 2 O is added upon C atom of the nutrient substance or its intermediate for O atom of H 2 O being combined with C atom to form CO 2 by organic acid decarboxylation and H atom of H 2 O being decomposed off with NADH or FADH 2 by dehydrogenases for entering into the respiratory chain,so energy of C atom is changed for H atomic energy and then gradually released off through the respiratory chain.