Enterokinase (EC 188.8.131.52) is a serine proteolytic enzyme, which can recognize the sequence of ASP ASP Lys (DDK) in the protein efficiently and specifically, hydrolyze the peptide bond at the C-terminal of lysine (Lys, K), produce cleavage, hydrolyze trypsinogen to trypsin in the organism. Because enterokinase has high specificity and efficient enzymatic cleavage, it is widely used in genetic engineering. Product development.
Natural enterokinase consists of a heavy chain of 115 kDa and a light chain of 35 kDa. The heavy chain anchors the cell membrane and the light chain has full enzymatic catalytic activity. The central region of light chain activity (235A. A., 26.2kda) secreted and expressed by E. coli is more active than that of bovine enterokinase, which is particularly suitable for enzymatic digestion of the protein. of genetic engineering fusion.
Remarks: (1) Some reagents may affect enzyme activity, such as> 2m urea,> 250mm NaCl,> 20mm β – moi,> 0.1% SDS,> Imidazole 50mm. If the sample contains these components, dialysis at 50 mm Tris HCl (ph8.0) is required.
(2) Phosphate can inhibit enterokinase activity, so phosphate buffer should not be used as an enzymatic cutting system.