Determine how much Acr-PEG-stuff you want/need and convert to moles
Calculate needed amount of PEG(3400)-NHS (mol to g – MW ~3220)
Determine how much of the pendant group to add – use 20% excess
Prepare either a 50 mM Tris buffer, pH 8.5 or a 50 mM sodium bicarbonate buffer, pH 8.4
React PEG-NHS and pendant group in ~100 ml of buffer in a round bottom flask for 2 hours
Pour liquid into a freeze-drying vessel and freeze in -80 ºC
Freeze-dry
Resuspend in PBS and dialyze in appropriately pore sized dialyzer for 3 days with 2 exchanges of PBS
Freeze the dialyzed product again at -80 ºC
Freeze-dry