Bis-PEG6-acid is a PEG derivative containing two terminal carboxylic acid groups. The hydrophilic PEG spacer can increase solubility in aqueous media. The terminal carboxylic acids can be reacted with primary amine groups in the presence of activators (e.g. EDC, or DCC) to form a stable amide bond.
Axispharm offers 3000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.