Disclosed is a method for refolding a protein or peptide that does not
contain essential disulfides and that contains at least one free cysteine
residue. Also disclosed are polymer IFN-.gamma. conjugates that have been
created by the chemical coupling of polymers such as polyethylene glycol
moieties to IFN-.gamma., particularly via a free cysteine in the protein.
Also disclosed are analogs of bioactive peptides that may be used to
create longer acting versions of the peptides, including analogs of
glucagon, glucagon-like peptide-1 (GLP-1), GLP-2, Gastric inhibitory
peptide (GIP), PYY, exendin, ghrelin, gastrin, amylin, and oxyntomodulin.