METHODS FOR MAKING PROTEINS CONTAINING FREE CYSTEINE RESIDUES

摘要

PROBLEM TO BE SOLVED: To provide a method of obtaining soluble proteins having at least one added free cysteines.SOLUTION: The method comprises the steps of: (a) obtaining a host cell capable of expressing the soluble protein having at least one added free cysteines; (b) exposing the host cell to a cysteine blocking agent forming a stable mixed disulfide with the at least one added free cysteines before the step (c); and (c) isolating the soluble protein from the host cell. The produced soluble proteins can be modified to increase their effectiveness, and such modifications include attaching a PEG moiety to form pegylated proteins.