Mast cell protease1(Mcpt1), alsoknown as beta-chymase, is a member of the Chymase family of c chymotrypin-­like serine proteases (1). mMcpt1is a mast cell protease predominantly expressed in intestinal mucosal mast cells where it promotes mucosal permeabiliy in intestinal allergic hypersensitvity reactions (2). Its activation is completed by the removal of a two residue N-­terminal propeptide by a dipeptidyl peptidase (Cathepsin C) (3). Like human a-Chymase, Mcpt1 is capable of the conversion of angiotensinI to angiotensin II, which plays a key role in the regulation of arterial pressure (4). Studies have shown that specific chymase inhibitors are able to diminsh the development of abdominal aortic aneurysm and reduce the adhesion formation after cardiac surgery in hamsters (5, 6). Therefore, the development of specific inhibitors of chymase activity has been a pharmacologic strategy to develop therapeutic agents.