Description_x000D_ General description_x000D_ The enzyme enterokinase is a serine protease that is encoded by a 3696 nucleotide cDNA that contains an open reading frame of 3057 nucleotides. The encoded precursor is cleaved to form an active protein that contains a 784 amino acid heavy chain followed by a 235 amino acid light chain that are linked by one or more disulfide bonds. The mRNA is found to be expressed only in small intestine and the protein is found in enterocytes of duodenum and proximal jejunum . The human enterokinase gene is localized to chromosome 21q21._x000D_ Application_x000D_ Enterokinase has been used in the activation of pancreatic enzyme preparation. It has been used for the activation and determination of trypsin activity in pancreatic enzyme secretion._x000D_ Biochem/physiol Actions_x000D_ The enterokinase enzyme is a glycoprotein that catalyzes the conversion of trypsinogen to trypsin, which activates the zymogens pancreatic digestive enzymes. Deficiency of this enzyme causes protein deficiency as zymogens do not get activated. Congenital deficiency of enteropeptidase leads to severe intestinal malabsorption with diarrhea, vomiting, and growth failure._x000D_ Physical form_x000D_ Sterile filtered through a 0.2 micron filter. Lyophilized from 10 mM Sodium Phosphate, pH 7.5 and 1 mM Calcium Chloride._x000D_ Reconstitution_x000D_ Centrifuge the vial prior to opening. Reconstitute in water to a concentration of 0.1-1.0 mg/mL. Do not vortex. This solution can be stored at 2-8°C for up to 1 week. For extended storage, it is recommended to further dilute in a buffer containing a carrier protein (example 0.1% BSA) and store in working aliquots at -20°C to -80°C.