Recombinant Enterokinase 100U (rEK)

Specifications and Use

Description

l          Recombinant Enterokinase (rEK) is the catalytic subunit of bovine enterokinase, which is expressed by the yeast Pichia pastoris and purified to yield a high enzyme activity preparation. rEK 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.

Contents

l          100units of rEK.

10× rEK buffer

Specifications

l          Volume: 1000µl.

Concentration: 0.1unit/µl

Unit Definition

l          One unit of rEK is the amount of enzyme that will cleave 20µg of thioredoxin-chloramphenicci acetyl transferase fusion protein containing an enterokinase cleavage site (Asp-Asp-Asp-Asp-Lys) to 90% completion at 37℃ in 16 hours under the assay conditions listed below.

Assay Conditions

l          Recombinant EK in 50mM Tris-HCl, pH 8.0, 1mM CaCl₂, 0.1% Tween-20, 20µg of fusion protein, and 1 unit rEK in a 30µl reaction volume incubated at 37℃.

Non-Specific Protease Activity Assay

l          A non-specific protease activity assay of rEK was performed using azocasein as substrate. The results show that rEK contains less than background levels of non-specific protease.

Storage Conditions

l          rEK in 50 mM Tris-HCl, pH 8.0, 500 mM NaCl and 50% glycerol should be stored at -20℃. Guaranteed stable for 1 year when stored properly.