This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gastrointestinal System, Subject name: Physiology
Activation of which of the following enzymes is responsible for acute pancreatitis? 
Select and explain. 
A. Phospholipase A2, B. Colipase, C. Procarboxypeptidase, D. ProElastase
A: Phospholipase A2
Answer: A: Phospholipase A2 
Explanation: Enzyme activated by trypsin is phospholipase A2. This enzyme splits a fatty acid off phosphatidylcholine (PC), forming lyso-PC. Lyso-PC damages cell membranes. It has been hypothesized that in Acute pancreatitis - a severe and sometimes fatal disease, phospholipase A2 is activated prematurely in the pancreatic ducts, with the formation of lyso-PC from the PC that is a normal constituent of bile. This causes disruption of pancreatic tissue and necrosis of surrounding fat.