Question

All enzymes of TCA cycle are located in the mitochondrial matrix except one which is located in the inner mitochondrial membrane in eukaryotes and in the cytosol in prokaryotes. Identify the enzyme.

• A. Succinate dehydrogenase
• B. Lactate dehydrogenase
• C. Isocitrate dehydrogenase
• D. Malate dehydrogenase

Answer 1

The correct option is A Succinate dehydrogenase

All the oxidative enzymes of TCA cycle are located in matrix except succinate dehydrogenase. This enzyme catalyses the conversion of succinic acid into fumaric acid. It is an integral protein complex that is tightly bound to the inner mitochondrial membrane. This enzyme is also the preferred marker enzyme for inner membranes when doing mitochondrial fractionations.