<unk>  is a form of<unk>  that is produced in the acinar cells of the pancreas, initially produced as an inactive zymogen and later activated in the duodenum by trypsin.<unk> s form a subfamily of serine proteases, characterized by a distinctive structure consisting of two beta barrel domains converging at the active site that hydrolyze amides and esters amongst many proteins in addition to elastin, a type of connective tissue that holds organs together.<unk>  1 is a serine endopeptidase, a specific type of protease that has the amino acid serine at its active site. Although the recommended name is<unk> , it can also be referred to as<unk> -1, pancreatopeptidase, PE, or serine<unk> . The first isozyme,<unk>  1, was initially thought to be expressed in the pancreas. However it was later discovered that it was the only chymotrypsin-like<unk>  that was not expressed in the pancreas. In fact,<unk>  is expressed in basal layers of epidermis (at protein level). Hence<unk>  1 has been renamed<unk>  1 (ELA1) or chymotrypsin-like<unk>  family, member 1 (CELA1). For a period of time, it was thought that ELA1 / CELA1 was not transcribed into a protein. However it was later discovered that it was expressed in skin keratinocytes. Clinical literature that describes human<unk>  1 activity in the pancreas or fecal material is actually referring to chymotrypsin-like<unk>  family, member 3B (CELA3B).
Pancreatic elastase
Alpha-amylase
Cholecystokinin
Intrinsic factor
Lactase
Neutrophil elastase
Gastric inhibitory polypeptide
Butyrate esterase