Question

Removal of hydrogen and CO${}_2$ from a substrate is called

• A. Decarboxylation
• B. Oxidation
• C. Oxidative decarboxylation
• D. Reductive decarboxylation

Answer 1

The correct option is C Oxidative decarboxylation

Oxidative decarboxylation reactions involve oxidation process which means removal of hydrogen followed by removal of carboxylate group with the formation of carbon dioxide. For example in citric acid cycle, isocitrate gives off a pair of hydrogen atoms (oxidation) and a molecule of carbon dioxide (decarboxylation and becomes) 5-carbon α-ketoglutarate. The pair of hydrogen atoms give two electrons and one H+to NAD+ forming NADH + H+. The enzyme isocitrate dehydrogenase catalyses the reaction in the presence of manganese ions.

Thus, the correct answer is option C.