This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Enzyme basics and serine proteases, Subject name: Biochemistry
Trypsin cleaves carboxy terminal of : 
Select and explain. 
A. Glutamate, B. Arginine, C. Glycine, D. Proline
B: Arginine
Answer: B: Arginine 
Explanation: Trypsin cleaves carboxy terminal of Basic amino acids (Arginine, Lysine). EXTRA READING ON THIS TOPIC Serine proteases: * Proteolytic enzymes with serine at their active site. * Amino acid triad in the active site of serine proteases - Serine, Histidine, Aspaate. Examples of serine proteases: Chymotrypsin, Trypsin, Elastase, Thrombin, Plasmin, Complements, Factors X and XI Serine Proteases differ in substrate specificity Chymotrypsin: Cleaves at Carboxy terminal of bulky Hydrophobic amino acids (Tryptophan, Tyrosine, Phenylalanine) Elastase: Cleaves at Carboxy terminal of small Neutral amino acids e.g. Glycine, Alanine