This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
All of the following could include the mechanism or function of oxigenases, EXCEPT: 
Select and explain. 
A. Incorporate 2 atoms of oxygen, B. Incorporate 1 atom of oxygen, C. Required for hydroxylation of steroids, D. Required for carboxylation of drugs
D: Required for carboxylation of drugs
Answer: D: Required for carboxylation of drugs 
Explanation: Carboxylation is a function of carboxylase enzymes which belong to the class of 'Ligases'. It is not a function of oxygenase enzymes. Monoxygenases incorporate one atom of oxygen and play an impoant role in hydroxylation of steroids. Dioxygenases incorporate 2 atoms of oxygen into the substrate. Ref: Harper's Illustrated Biochemistry 27th Edition, Page 96, 97; Enzyme Assays: High-Throughput Screening, Genetic Selection and Fingerprinting edited by Jean-Louis Reymond, 2006, Page 85.