Aldehyde PEGylation kinetics: a standard protein versus a pharmaceutically relevant single chain variable fragment.

The mPEG-aldehyde PEGylation with two different PEG sizes and two proteins was experimentally determined with respect to yield, conversion, and selectivity. The kinetic behavior of these PEGylation reactions was simulated using a numerically solved set of differential equations. We show that the assumption of an inactivation of mPEG-aldehyde is crucial for the simulation of the overall PEGylation and that the inactivation is pH-dependent.