Application

Enterokinase is a member of the S1 peptidase family. In vivo, it is responsble for the proteolytic activation of trypsin from trypsinogen. Enterokinase is used for site specific cleavage of recombinant fusion proteins containing an accessible enterokinase recognition site for removal of affinity tags.

Enterokinase from bovine intestine has been used in a study to assess duodenase as a potential activator of cascade digestive proteases. Enterokinase from bovine intestine has also been used in a study to investigate an inhibitor of enteropeptidases and trypsin from the bovine duodenum.

The enzyme from Sigma has been used to compare the specific activity with that of purified, recombinant bovine enterokinase (light chain) overexpressed in Escherichia coli.

Unit Definition

One unit will produce 1.0 nanomole of trypsin from trypsinogen per min at pH 5.6 at 25 °C.

Physical form

supplied as a solution in 20 mM Tris-HCl, 200 mM NaCl, and 50% glycerol

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, wherein, the light and the heavy chains are linked by two disulfide bridges. Native enterokinase is composed of an 800 amino acid heavy chain and a 235 amino acid light chain. It is a glycoprotein containing 35% carbohydrate. The polypeptide chain of trypsinogen is hydrolyzed only after an -(Asp)₄-Lys- sequence. This cleavage site is incorporated into the FLAG tag. The FLAG^® protein expression system is based on the fusion of the 8 amino acid FLAG tag to the recombinant protein of choice. Cleavage by enterokinase removes the FLAG tag from the fusion protein. The enzyme is inhibited by soybean trypsin inhibitor. Enterokinase is typically used in protein modification and amino acid sequence determination.

Physical properties

28 kDa light chain form

法律信息

FLAG is a registered trademark of Sigma-Aldrich Co. LLC

TWEEN is a registered trademark of Croda International PLC