Ald-CH2-PEG4-CH2CO2tBu

Ald-CH2-PEG4-CH2CO2tBu is a PEG linker with aldehyde and t-butyl moieties. Aldehyde is reactive to hydrazide and aminooxy groups which are commonly used in biomolecular probes for labeling and crosslinking carbonyls (oxidized carbohydrates). The t-butyl group can be removed under acidic conditions. The hydrophilic PEG linker increases the water solubility of the compound.