01 September 2014

Seperoxides during Ischemia and Reperfusion

The Electron Transport Chain Donates A Pair of Electrons to O2, thus producing two molecules of H2O. What happens when Oxygen is limited or in low supply (Ischemia)? What happens when Oxygen supply is restored (reperfusion)?

When Oxygen availability is extremely low (Ischemia), electrons get backed-up in the ETC. And when an oxygen molecule is nearby, single electrons may "leak/jump" onto that oxygen molecule inappropriately. This produces Superoxides (oxygen radicals). In the same vain, when oxygen is restored to the cell (reperfusion), the over-crowded electron transport chain will unload single electrons onto oxygen, creating many superoxides. This continues until the ETC re-equilibrates. This is known as reperfusion injury. 

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