The Citric Acid Cycle

Alcohols

Oxidation-Reduction

Oxidation-Reduction in Organic Chemistry

Succinate is first oxidized in a dehydrogenation reaction (catalyzed by succinate dehydrogenase), converting succinate into an alkene, fumarate. This oxidiation reduces FAD into FADH₂.

Fumarate is then hydrated to form the alcohol malate, which is then oxidized to form the aldehyde, oxaloacetate, converting NAD⁺ to NADH. Oxaloacetate is the form which initial combined with acetyl CoA, so the cycle is complete.