This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of protein and amino acid, Subject name: Biochemistry
The 'catalytic triad' in the active centre of proteases contains the following amino acids? 
Select and explain. 
A. Ser, Lys, Arg, B. Ser, His, Asp, C. His, Phe, Trp, D. None of the above
B: Ser, His, Asp
Answer: B: Ser, His, Asp 
Explanation: A catalytic triad is a group of three amino acids that are found in the active sites of some proteases involved in catalysis.In chymotrypsin, the catalytic triad is made from serine, histidine, and aspaate.Harper 30th edition pg: 93