CHO-CH2-PEG2-CH2tBu-ester linker contains aldehyde and a t-butyl ester. Aldehyde readily react with hydrazide and aminooxy groups. The t-butyl ester can be de-protected under acidic conditions to form free acid. The hydrophilic PEG linker can increase the water solubility of the compound.
Axispharm offers 3000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.