Action

• Recombinant Enterokinase cuts the following sequence

Asp-Asp-Asp-Asp-Lys - X - X - X - X

• It has minimal requirements for specific amino acids in the P1’ and P4’ positions* 

* Natural substrates have a propensity for Gly or Ser at P3’ and/or P4’ to ensure regular secondary 

structure formation does not limit accessibility to the cleavage site.

• This independence makes enterokinase ideal for the removal of fusion proteins and/or tags 

with the subsequent generation of an authentic N-terminus.

• Many companies monitor activity by following the cleavage of a protein. The fusion partners used 

vary widely.

• The assay conditions employed also vary widely and so, the units of activity are often defined 

differently.

• Paras uses one of the most credible industry standard methods for recording the activity of the 

enzyme.

Recombinant Enterokinase

What 

is Protein Purification

What 

are Protein Tags?

Protein tags are peptide sequences genetically grafted 

onto a recombinant protein which are often removable by 

chemical agents or by enzymatic means. One such example 

are affinity tags which are appended to proteins so that 

they can be purified from their crude biological source 

using an affinity technique. 

Enterokinase can be used to cleave a fusion protein con-

taining a C-terminal affinity tag to produce a target protein 

following protein purification.

Protein purification is a series of processes intended to 

isolate one or more proteins from a complex structure. It is 

vital for the characterisation of the function, structure and 

interactions of the protein of interest. 

One effective technique is the tagging of proteins to engi-

neer an antigen peptide tag onto a protein, and then purify 

the protein through a column. Once finished, the tag can 

be cleaved from the protein by a protease.

Enterokinase is a type 2 transmembrane serine protease produced by cells in the duodenum which are 

involved in the body’s digestive system. It is responsible for the initial activation of pancreatic proteo-

lytic proenzymes that catalyses the conversion of trypsinogen to trypsin. Enterokinase’s specificity 

makes it an ideal tool for biotechnological and biochemical removal of fusion proteins and tags.

Molecular weight of enterokinase varies from 82 - 140 kD (113 kD protein core) and 35 - 62 kD for its 

disulfide-linked heavy-chain and light-chain, respectively, depending on the organism.

As a human enzyme, enterokinase is 

1019 amino acids in length containing 

14 disulfide bonds, 18 potential N-gly-

cosylation sites and a N-myristoyl lipda-

tion site as the N-terminus.

Enterokinase’s catalytic light chain is 

235 amino acids in length and con-

tains 4 disulfide bonds.

Enterokinase deficiency is a life threat-

ening intestinal malabsorption disor-

der.

Specifically cleaves the bond between 

Lys23 and lle24 in human trypsin-1 

and the equivalent peptide bond in 

other trypsin family members.

DISCOVERED BY NOBEL PRIZE WINNER 

IVAN 

PAVLOV

, IT IS THE FIRST KNOWN 

ENZYME

 TO 

ACTIVATE OTHER ENZYMES.