PEGProtein Conjugation Protocols

The concentration of protein in the reaction mixture is important in determining the final yield of coupling. The best coupling yields are normally obtained at protein concentrations of 1-5 mg mL. At higher protein concentrations, higher yields may be expected, whereas the yield drops significantly at protein concentration below 1 mg mL. Therefore, it is important to know the protein concentration before the coupling procedure. This can be determined by amino acid analysis, UV, or classic...

Characterization of PEG Reagents

Before conducting any coupling reaction, it is generally advised that one verify the amount of active moiety in the activated PEG batch. This is important especially when using a reactive PEG from a vial that was opened previously (see Note 2). For this control, several methods are available depending upon the PEG reactive moiety, among which are NMR and colo-rimetric tests. Any reactive PEG can be analyzed by both 1H- and 13C-NMR analysis. Both techniques are straightforward and accurate....