The benzaldehyde group readily reacts with primary amines, aminooxy and hydrazide. T-Buty ester can be hydrolyzed to form a free acid that can be used to conjugate with amine-bearing molecules. The PEG spacer increase the solubility of the resulting complex in aqueous media.
Axispharm offers 3000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.