Patent ID: 7785828
Filing Date: 2010-08-31
Classification: C07K,C12N

Abstract:
1. A method of preparing a cysteine-containing polypeptide recombinantly expressed in a cell comprising a) recombinantly expressing in a cell a cleavable and soluble fusion protein comprising an amino-terminal tag domain, a first domain encoding a heterologous polypeptide, a second domain encoding the cysteine-containing polypeptide, and a cleavage site interposed between the first and second domains; b) separating the fusion protein from at least some cell components based on the binding of the tag domain and a binding agent; and c) contacting the fusion protein and a cleaving agent that cleaves at the cleavage site, thereby cleaving the fusion protein to produce the cysteine-containing polypeptide as a cleavage product, wherein the cysteine-containing polypeptide has a purity of at least 50%, wherein steps (b) and (c) are carried out in the presence of a reducing agent to prevent misfolding of the fusion protein.