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Glucose oxidation reaction is a cellular biochemical process that uses oxygen to oxidize glucose to carbon dioxide and water; the chemical energy released from oxidation is used to convert ADP to ATP.〔H. Lodish, A. Berk, S. Zipursky, Molecular Cell Biology. 4th edition (W. H. Freeman, New York, 2000)〕 This process is essential and ubiquitous in living systems, and is the major energy source for cells. The net reaction is shown below, a single glucose molecule consumes six molecules of oxygen, producing six molecules of carbon dioxide and six water molecules. The energy generated can be used to produce a maximum of 38 ATP from ADP and phosphate ion. Glucose oxidation contains four stages.〔RSC, Chemistry for biologists:respiration (available at http://www.rsc.org/Education/Teachers/Resources/cfb/respiration.htm)〕 First step is glucose hydrolysis, which takes place in the cell cytosol. During this step, one glucose molecule is broken down into two pyruvates. Energy generated in this step is stored both in the form of NADH and ATP. Two molecules of NADH and two molecules of ATP are produced from glycolysis of one glucose molecule. The pyruvate produced from glycolysis can be processed by pyruvate dehydrogenase to generate acetyl-CoA and carbon dioxide.〔K. J. Angelides, G. G. Hammes, Mechanism of action of the pyruvate dehydrogenase multienzyme complex from Escherichia coli., Proc. Natl. Acad. Sci. U. S. A. 75, 4877–4880 (1978).〕 Energy released is used to produce NADH. This transformation is known as oxidative decarboxylation of pyruvate, which happens in the mitochondria of eukaryotic cells and in the cytosol of prokaryotic cells. After acetyl-CoA is formed, it can enter the mitochondrial matrix and participate in the Krebs cycle, the second major step in glucose oxidation reaction. Acetyl Co-A is oxidized into carbon dioxide and at the same time producing NADH from NAD and FADH2 from FAD. The Krebs cycle also generates ATP. The last step of glucose oxidation is oxidative phosphorylation, also known as the electron transport chain. All the NADH and FADH2 molecules produced in previous steps are oxidized, and the energy stored in them is transferred to ATP. The electrons are transferred to oxygen with addition of two protons to form water〔G. M. Cooper, in The Cell: A Molecular Approach. 2nd edition, (Sinauer Associates, Inc., Sunderland (MA), 2000)〕 ==References== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Glucose oxidation reaction」の詳細全文を読む スポンサード リンク
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