Purification of a PEGylated single chain Fv

► PEGylation of single chain variable fragment with 5 kDa and 30 kDa PEG. ► Implementation of preparative chromatographic purification of PEGylated single chain variable fragment. ► Two-step purification using IEX and HIC leading to a purity of more than 98%. ► Use of arginine-chloride in IEX for improved resolution. ► Maintenance of biological activity of PEGylated single chain variable fragment, determined in vitro.