This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of lipid, Subject name: Biochemistry
[{'content': 'The only energy-requiring step in fatty acid oxidation is catalyzed by ______ enzyme? \nSelect and explain. \nA. Thiokinase, B. Acyl co A dehydrogenase, C. Thiolase, D. Beta hydroxy Acyl co A dehydrogenase', 'role': 'user'}, {'content': "Answer: A \nExplanation: In the presence of ATP and coenzyme A, the enzyme acyl-CoA synthetase (thiokinase) catalyzes the conversion of a fatty acid to acyl-CoA. Reference: Harper's Illustrated Biochemistry 30th Edition Pg 224", 'role': 'assistant'}]