Recombinant Animal Origin Free Enterokinase (Rec-AOF-EK) is a highly purified preparation of the catalytic subunit (light chain) of bovine Enterokinase. A serine protease, it recognizes the identical cleavage site as the native enzyme (AspAspAspAspLys↓) and has similar enzymatic activity.
It is commonly used for removal of fusion tags for production of biopharmaceuticals.
Rec-AOF-EK is produced in E.coli and purified to yield the highest activity available, and is qualified for specific cleavage of appropriate fusion proteins.
Genetically engineered fusion tags allow the purification of almost all proteins without prior knowledge of their biochemical properties. When properly designed and judiciously used, they enhance the solubility and promote proper folding of the protein of interest, leading to recovery of more functional protein.
An ideal choice for such a "universal" fusion protein cleaving method is use of the mammalian enzyme Enterokinase (enteropeptidase). Enterokinase is the physiological activator of trypsinogen and cleaves with high specificity after the sequence (Asp.Asp.Asp.Asp)-Lys↓.
Porcine and bovine Enterokinases were isolated and were found to have very high M.W. (150,000 Da) and 35% glycosylations. The protein is primarily made up of a heavy and light chain connected by one or more disulfide bonds. The light chain is the primary catalytic subunit of the enzyme.