Methylamino-PEG4-t-butyl ester is a PEG linker containing a methylamine group and a t-butyl ester. The hydrophilic PEG spacer increases solubility in aqueous media. The methylamine group is reactive with carboxylic acids, carbonyls (ketone, aldehyde) etc. The t-butyl protected carboxyl group can be deprotected under acidic conditions.
