This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Phenylalanine and Tyrosine metabolism Detail, Subject name: Biochemistry
[{'content': 'The difference in molecular weight between Phenylalanine & Tyrosine is by : \nSelect and explain. \nA. 17, B. 16, C. 64, D. 32', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Usually students tend to mark 17 as the answer. Phenylalanine gets conveed to Tyrosine by enzyme Phenylalanine Hydroxylase. Most Hydroxylases are Mono-oxygenases i.e. EC No. 1. In hydroxylation reactions, only one oxygen atom from the molecular oxygen is added because H was already present in the phenylalanine. So, change in molecular weight is by 16 and NOT 17. Extra Information: Phenylalanine is an essential amino acid and its only role in the body is to give rise to tyrosine.', 'role': 'assistant'}]