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
[{'content': 'A common feature of all serine proteases is: \nSelect and explain. \nA. Autocatalytic activitation of zymogen precursor, B. Tight binding of pancreatic trypsin inhibitor, C. Cleavage of protein on the carboxyl site of serine residues, D. Presence of Ser-His_Asp catalytic triad at the active site', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Serine proteases are a group of powerful enzymes that cut peptide bonds of few proteins. They help in digestion, immunity, clotting and also aid in sperm entering the egg. The active site of serine proteases contain three amino acids serine, histidine and aspaate together referred as the catalytic triad. Ref: Textbook of Biochemistry By DM Vasudevan, 3rd Edition, Page 35', 'role': 'assistant'}]