Principles of Biochemistry

It acts as a common pathway for the oxidation of carbohydrate, lipids and proteins because glucose, fatty acids and many aminoacids are metabolised to acetyl-CoA which is finally oxidises in the citric acid cycle.The reducing equivalents in the form of hydrogen and electrons are formed by the action of specific dehydrogenation during the oxidation of acetyl CoA in the cycle. These reducing equivalents then enter the respiratory chain when  large amounts of high energy phosphate are generated by the oxidative phosphorylations.

The enzymes of citric acid cycle are located in the mitochontrial matrix either  or attached with inner mitochondrial membrane which facilitates the transfer of reducing equivalents to the adjacent enzymes of electron transport chain which is situated in the inner mitochandrival membrane. The citric acid cycle is amphibolis(dual) in nature.