This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of carbohydrate, Subject name: Biochemistry
The conversion of propionyl CoA to succinyl CoA requires the following vitamins/coenzymes 
Select and explain. 
A. Thiamine pyrophosphate, B. FAD and NAD+, C. Coenzyme A, D. Biotin and B12
D: Biotin and B12
Answer: D: Biotin and B12 
Explanation: Propionate is a major precursor of glucose in ruminants; It enters gluconeogenesis the citric acid cycle. After esterification with CoA, propionyl-CoA is carboxylated to d-methylmalonyl-CoA, catalyzed by propionyl-CoA carboxylase, a biotin-dependent enzyme.l-methylmalonyl-CoA undergoes isomerization to succinyl-CoA catalyzed by methylmalonyl-CoA mutase. Methylmalonyl-CoA mutase is a vitamin B12-dependent enzyme, and in deficiency methylmalonic acid is excreted in the urine (methylmalonic aciduria).Ref: Harper&;s Biochemistry; 30th edition; Chapter 19; Gluconeogenesis & the Control of Blood Glucose