This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Mechanisms of Enzyme Action, Subject name: Biochemistry
Carboxylases requires - 
Select and explain. 
A. Vitamin B12, B. Folic acid, C. Niacin, D. Biotin
D: Biotin
Answer: D: Biotin 
Explanation: Ans. is 'd' i.e., Biotin o Biotin is a coenzyme for carbon dioxide fixation reactions.o It serves as prosthetic group of ATP-dependent carboxylase, i.e., in carboxylation reactionQ,o It acts as coenzyme tor acetyl-CoA carboxylaseQ, propionyl-CoA carboxylaseQ, pyruvate carboxylaseQ and metbylcartonyl-CoA carboxylase.