Uses
Typical conditions for fusion protein cleavage:
Adjust the concentration of the fusion protein to 1.5 mg/ml and a pH between 7.0-8.0 with 500 mM Tris-HCl, pH 8.0, 2.0 mM CaCl
2, and 1% Tween
20
Add enterokinase to fusion protein solution at a ratio of ~ 0.02 units per 1 mg fusion protein and mix
Incubate reaction mixture at ~25 °C for 16 hours
Definition
An enzyme found in the small intestine, which converts trypsinogen into trypsin.
General Description
Enterokinase is a highly specific serine protease that is used for the removal of the FLAG peptide from N-terminal and Met-N-terminal fusion proteins. It does not remove the C-terminal FLAG.
Biochem/physiol Actions
Enterokinase is a membrane bound serine protease that specifically and rapidly converts trypsinogen to trypsin, thereby, triggering the conversion of other zymogens to active enzymes. It has a molecular mass of approximately 150 kDa. The enzyme is a heterodimer consisting of 35-47 kDa subunits. The light and the heavy chains are linked by two disulfide bridges. It is a glycoprotein containing 35% carbohydrate. The polypeptide chain of trypsinogen is hydrolyzed only after an -(Asp)4-Lys- sequence. The enzyme is inhibited by soybean trypsin inhibitor. Enterokinase is typically used in protein modification and amino acid sequence determination.
Description
Enterokinase (rEK) Bovine Recombinant is the catalytic subunit of bovine enterokinase, which is expressed by E. Coli and purified to yield a high enzyme activity preparation. EK recognizes the sequence Asp-Asp-Asp-Asp-Lys and cleaves the peptide bond after the lysine residue. The enzyme can be used to cleave any fusion protein that carries this sequence. Recombinant Bovine Enterokinase is a single glycosylated polypeptide chain containing 235 amino acids and having an MW of ~28kDa.
Background
Enteropeptidase or enterokinase is an enzyme involved in human digestion. It is produced by cells in the duodenum wall, and is secreted from duodenum's glands, the crypts of Lieberk?hn, whenever ingested food enters the duodenum from the stomach. Enteropeptidase has the critical job of turning trypsinogen (a zymogen) to trypsin, indirectly activating a number of pancreatic digestive enzymes. Enteropeptidase is a serine protease enzyme (EC 3.4.21.9). Enteropeptidase is a part of the Chymotrypsin-clan of serine proteases, and is structurally similar to these proteins.
