This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Enzyme kinetics, Subject name: Biochemistry
[{'content': 'Unit of Km is: \nSelect and explain. \nA. second-1, B. Moles second-1, C. Millimoles, D. Millimoles Litre-1', 'role': 'user'}, {'content': "Answer: D \nExplanation: The Km is the substrate concentration at 1/2 Vmax. As Km is the concentration, unit of Km will be the unit of concentration Km is a measure of a substrate's affinity for the enzyme. It is inversely propoional to the affinity.", 'role': 'assistant'}]