This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Beta oxidation of fatty acids, Subject name: Biochemistry
[{'content': 'The enzyme involved in the activation for fatty acids beta oxidation is? \nSelect and explain. \nA. Thiophorase, B. Thiokinase, C. Thiolase, D. Thioesterase', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Fatty acids must first be conveed to an active intermediate before oxidation. This is the only step in the oxidation of a fatty acid that requires energy from ATP. In the presence of ATP and coenzyme A, the enzyme acyl-CoA synthetase (thiokinase) catalyzes the conversion of fatty acid (or FFA) to an "active fatty acid" or acyl-CoA, using one high-energy phosphate and forming AMP and PPi. The PPi is hydrolyzed by inorganic pyrophosphatase with the loss of a fuher high-energy phosphate, ensuring that the overall reaction goes to completion. Acyl-CoA synthetases are found in the endoplasmic reticulum, peroxisomes, and on the outer membrane of mitochondria.', 'role': 'assistant'}]