Abstract: 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 FADH2 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 H2O to change C with H, which H2O is added upon C atom of the nutrient substance or its intermediate for O atom of H2O being combined with C atom to form CO2 by organic acid decarboxylation and H atom of H2O being decomposed off with NADH or FADH2 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.

Key words: biochemistry, active mechanism, gradually energesis, biological oxidation