Krebs Cycle: The Central Hub of Energy Metabolism - Exploring the Citric Acid Cycle

The Krebs Cycle performs multiple essential functions, including generating ATP, producing NADH and FADH2, and converting pyruvate into acetyl-CoA.

The Krebs Cycle consists of a series of eight enzymatic reactions that occur in a cyclic manner.

Acetyl-CoA, derived from the breakdown of carbohydrates, fats, and proteins, is the molecule that enters the Krebs Cycle.

The first reaction of the Krebs Cycle is the condensation of acetyl-CoA with oxaloacetate to form citrate, catalyzed by the enzyme citrate synthase.

The decarboxylation of α-ketoglutarate to succinyl-CoA, catalyzed by the enzyme α-ketoglutarate dehydrogenase, is the reaction that produces the most ATP in the Krebs Cycle.

The final product of the Krebs Cycle is oxaloacetate, which is regenerated to start the cycle again.

The Krebs Cycle directly produces 2 molecules of ATP per glucose molecule.

NADH and FADH2 are electron carriers that transfer electrons to the electron transport chain, where ATP is generated through oxidative phosphorylation. They are also involved in the decarboxylation reactions of the Krebs Cycle.

The conversion of isocitrate to α-ketoglutarate is catalyzed by the enzyme isocitrate dehydrogenase.

The decarboxylation of α-ketoglutarate to succinyl-CoA is catalyzed by the enzyme α-ketoglutarate dehydrogenase.

The conversion of succinyl-CoA to succinate, catalyzed by the enzyme succinyl-CoA synthetase, involves the transfer of a high-energy phosphate group to GDP to form GTP.

The oxidation of succinate to fumarate is catalyzed by the enzyme succinate dehydrogenase.

The addition of water to fumarate to form malate is catalyzed by the enzyme fumarase.

The oxidation of malate to oxaloacetate is catalyzed by the enzyme malate dehydrogenase.