Enterokinase (EK) is a duodenal protease involved in digestion by activating trypsinogen into trypsin, which in turn activates other pancreatic enzymes. EK specifically cleaves after the sequence Asp-Asp-Asp-Asp-Lys (DDDDK↓) and is inactive if a proline follows the site. Recombinant bovine enterokinase (rbEK) shows higher activity than EK from other species and is widely used in biochemical applications. It is a glycosylated single-chain protein of ~200 amino acids, tagged with C-terminal 6×His for Ni²⁺ affinity purification and easy removal after digestion. The purified rbEK has a molecular weight of ~40 kDa and is fully biologically active.
Enterokinase (EK) is a serine protease produced in the duodenum and involved in mammalian digestion. It activates trypsinogen to trypsin, thereby indirectly initiating the activation of pancreatic digestive enzymes. EK specifically cleaves after the recognition sequence Asp-Asp-Asp-Asp-Lys, but is inactive if a proline follows the cleavage site. This recombinant bovine enterokinase is the light chain catalytic subunit, comprising a single glycosylated polypeptide chain corresponding to residues Ile801–His1035 of the native protein (Accession # P98072). Expressed in Pichia pastoris under animal-free conditions, the enzyme is highly active and suitable for applications in drug and vaccine development. A C-terminal 6×His tag is included to allow efficient removal by Ni²⁺ affinity chromatography following cleavage reactions.
Enterokinase is a member of the trypsin family of serine proteases. The precursor protein is cleaved into two chains which then forms a heterodimer linked by a disulfide bond. The heavy chain anchors enterokinase in the intestinal brush border membrane and the light chain is the catalytic subunit, which initiates conversion activation of a subset of pancreatic proteolytic proenzymes. Enterokinase is the physiological activator of trypsinogen and has a specificity for the sequence (Asp)4-Lys-Ile. The mature trypsin in turn activates other proenzymes including chymotrypsinogen, procarboxypeptidases, and proelastases. In addition, Enterokinase is a tool protease widely utilized in the cleavage of recombinant fusion proteins.
Human Kallikrein 7 is a member of the tissue kallikrein family of extracellular serine proteases that is made up of 15 members. It is predominantly expressed in the skin. A major physiological function of Kallikrein 7 is to regulate the desquamation process (the shedding of corneocytes from the outer layer of the epidermis) through proteolysis of the intercellular adhesive structures between corneocytes. Dysregulation of Kallikrein 7 has been linked to several inflammatory skin diseases including atopic dermatitis, psoriasis, and Netherton syndrome. Studies have shown that Kallikrein 5 is a potential physiological activator for Kallikrein 7. The proform of Kallikrein 7 can be activated by thermolysin.