فسفرة تأكسدية
الفسفرة التأكسدية Oxidative phosphorylation هو عبارة عن مسار استقلابي metabolic pathway يستخدم الطاقة الناتجة عن الأكسدة للمواد الغذائية لإنتاج آ.تي.بي. مع ان كافة أشكال الحياة على الأرض تستخدم مجالا وساعا من المغذيات المختلفة ، فإن الجميع يقوم بإجراء فسفرة تأكسدية إنتاج الآ تي بي ، الجزيئة الحاملة للطاقة من عملية الاستقلاب. يعتبر هذا المسار فعالا جدا لتخخزين الطاقة إذا ما قورن بعمليات التخمير fermentation الحيوية البديلة كما في حالة تحلل الغليكوز glycolysis
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
مثبطات
هناك العديد من العقارات والمواد السامة المعرفة جيداً التي تمنع الفسفرة التأكسدية. Although any one of these toxins only inhibits one enzyme in the electron transport chain, inhibition of any step in this process will halt the rest of the process. For example, if oligomycin inhibits ATP synthase, protons cannot pass back into the mitochondrion.[1] As a result, the proton pumps are unable to operate, as the gradient becomes too strong for them to overcome. NADH is then no longer oxidized and the citric acid cycle ceases to operate because the concentration of NAD+ falls below the concentration that these enzymes can use.
| المركبات | الاستخدام | التأثير على الفسفرة التأكسدية |
|---|---|---|
| سيانيد أول أكسيد الكربون |
سموم | Inhibit the electron transport chain by binding more strongly than oxygen to the Fe–Cu center in cytochrome c oxidase, preventing the reduction of oxygen.[2] |
| Oligomycin | مضاد حيوي | Inhibits ATP synthase by blocking the flow of protons through the Fo subunit.[1] |
| CCCP 2,4-Dinitrophenol |
السموم | Ionophores that disrupt the proton gradient by carrying protons across the membrane. This uncouples proton pumping from ATP synthesis.[3] |
| Rotenone | مبيدات حشرية | Prevents the transfer of electrons from complex I to ubiquinone by blocking to the ubiquinone-binding site.[4] |
مراجع
- ^ أ ب Joshi S, Huang YG (1991). "ATP synthase complex from bovine heart mitochondria: the oligomycin sensitivity conferring protein is essential for dicyclohexyl carbodiimide-sensitive ATPase". Biochim. Biophys. Acta. 1067 (2): 255–8. PMID 1831660.
- ^ Tsubaki M (1993). "Fourier-transform infrared study of cyanide binding to the Fea3-CuB binuclear site of bovine heart cytochrome c oxidase: implication of the redox-linked conformational change at the binuclear site". Biochemistry. 32 (1): 164–73. PMID 8380331.
- ^ Heytler PG (1979). "Uncouplers of oxidative phosphorylation". Meth. Enzymol. 55: 462–42. PMID 156853.
- ^ Lambert AJ, Brand MD (2004). "Inhibitors of the quinone-binding site allow rapid superoxide production from mitochondrial NADH:ubiquinone oxidoreductase (complex I)". J. Biol. Chem. 279 (38): 39414–20. PMID 15262965.
قراءات أخرى
تمهيدية
- Nelson DL (2004). Lehninger Principles of Biochemistry (4th ed ed.). W. H. Freeman. ISBN 0-716-74339-6.
{{cite book}}:|edition=has extra text (help); Unknown parameter|coauthors=ignored (|author=suggested) (help) - Schneider ED (2006). Into the Cool: Energy Flow, Thermodynamics and Life (1st ed ed.). University of Chicago Press. ISBN 0-226-73937-6.
{{cite book}}:|edition=has extra text (help); Unknown parameter|coauthors=ignored (|author=suggested) (help)
متقدمة
- Nicholls DG (2002). Bioenergetics 3 (1st ed ed.). Academic Press. ISBN 0-125-18121-3.
{{cite book}}:|edition=has extra text (help); Unknown parameter|coauthors=ignored (|author=suggested) (help) - Haynie D (2001). Biological Thermodynamics (1st ed ed.). Cambridge University Press. ISBN 0-521-79549-4.
{{cite book}}:|edition=has extra text (help) - Rajan SS (2003). Introduction to Bioenergetics (1st ed ed.). Anmol. ISBN 8-126-11364-2.
{{cite book}}:|edition=has extra text (help) - Wikstrom M (Ed) (2005). Biophysical and Structural Aspects of Bioenergetics (1st ed ed.). Royal Society of Chemistry. ISBN 0-854-04346-2.
{{cite book}}:|edition=has extra text (help)
وصلات خارجية
مصادر عامة
- Animated diagrams illustrating oxidative phosphorylation Wiley and Co Concepts in Biochemistry
- Oxidative phosphorylation Metabolic Pathways of Biochemistry, the online reference of metabolism for students and teachers, at George Washington University
- ATP synthase - the rotary engine in the cell Brief introduction, including videos of microscope images of the enzyme rotating, at Tokyo Institute of Technology
- On-line biophysics lectures Antony Crofts, University of Illinois at Urbana-Champaign
مصادر بنيوية
- Animations of the ATP synthase Hongyun Wang and George Oster, University of California, Berkeley
- PDB molecule of the month:
- Interactive molecular models at Universidade Fernando Pessoa: