( Recombinant Enterokinase for highly s...)Efficient Cleavage of Fusion Proteins to Yield Native Amino Termini

Recombinant Enterokinase for highly specific digestion of purified proteins or proteins in crude extracts

Ed Marsh * Johanna Claycomb * ChaoFeng Zheng * Denise Wyborski * John C. Bauer * Joseph A. Sorge * A.K. Bernardino * Peter Vaillancourt
Stratagene Cloning Systems, Inc.

Stratagene introduces recombinant Enterokinase, an efficient, sitespecific protease that cleaves at the carboxy terminus of its recognition target. Cleavage of fusion proteins that contain the enterokinase (EK) recognition sequence positioned between an Nterminal purification tag and the Cterminal polypeptide of interest results in Cterminal fusion partners that have no extraneous amino acids derived from the cleavage site. Thus, recombinant proteins with native amino acid sequence are produced. Stratagene's purified Enterokinase is free of contaminating proteases, functions efficiently over a wide range of reaction conditions and is provided with Soybean Trypsin Inhibitor Agarose (STI Agarose) for rapid and quantitative removal of EK from digests.

figure 1

Site-specific proteases and their cognate target amino acid sequences are often used to remove the fusion protein tags that facilitate enhanced expression, solubility, secretion or purification of the fusion protein. The serine protease enterokinase (EK) is particularly attractive because it cleaves after the C-terminal amino acid of its recognition site, (aspartic acid)₄lysine. This cleavage produces fusion proteins that have native amino termini following removal of N-terminal tags by cleaving with EK (figure 1). In the past, the use of EK for fusion protein cleavage was hampered by the generally poor quality of the commercially a
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