Polyethylene glycol-conjugated pharmaceutical proteins

Polyethylene glycol (PEG)-conjugated proteins belong to a new class of biom olecules that are neither proteins nor polymers, but which are hybrids of t he two. PEG conjugation of biopharmaceuticals is now common practice in eff orts to achieve sustained clinical response. However, very little is known about the strategies and criteria used to produce a well-characterized pegy lated biomolecule. In this review, the issues of pegylation reagent selecti on, reaction conditions, process considerations and purification will be ad dressed, as well as biochemical and biological characterizations. The isola tion of positional isomers and the determination of pegylation sites will a lso be included.