Question

All enzymes of TCA cycle are located in the mitochondrial matrix except one which is located in inner mitochondrial membranes in eukaryotes and in cytosol in prokaryotes. This enzyme is:-

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

Answer 1

Answer: (A)

Succinate dehydrogenase

All enzymes of TCA(tri-carboxylic Acid cycle) are located in the mitochondrial matrix except one which is located in inner mitochondrial membranes in eukaryotes and in the cytosol in prokaryotes i.e., Succinate dehydrogenase.

This enzyme catalyses the removal of two hydrogens from succinate in the sixth reaction of TCA. In this reaction, a molecule of FAD, a coenzyme similar to NAD, is reduced to FADH${}_2$ as it takes hydrogen from the succinate. The final product of this reaction is Fumarate.

So, the correct answer is 'Succinate dehydrogenase'.