N-(Azido-PEG3)-PEG4-t-butyl ester is a branched PEG linker with an azide group and a t-butyl ester group. The azide group reacts with alkyne or cyclooctyne in Click Chemistry reaction.
AxisPharm offers 5000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.