This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cellular Pathology, Subject name: Pathology
Which is a serine protease: 
Select and explain. 
A. Pepsin, B. Trypsinogen 1, C. HIV enzyme, D. Chymotrypsin
B: Trypsinogen 1
Answer: B: Trypsinogen 1 
Explanation: Ans. b. Trypsinogen 1Inherited predisposition to pancreatitisGene (chromosome location)Protein productFunctionPRSSl (7q34)Serine protease 1 (trypsinogen 1)Cationic trypsin. Gain-of-function mutations prevent self- inactivation of trypsinSPINK1 (5q32)Serine peptidase inhibitor, Kazal type 1Inhibitor of trypsin. Mutations cause loss-of-function, increasing trypsin activityCTRC (lp36)Chymotrypsin C (caldecrin)Degrades trypsin, protects the pancreas from trypsin-relatedinjuryCPA1 (7q32)Carboxypeptidase A1Exopeptidase involved in regulating zymogen activation