Hydroxy-PEG-Acetic acid

The HO-PEGn-CH₂COOH series, featuring HO-PEG4-CH₂COOH as a representative product, is a heterobifunctional PEG spacer containing a hydroxyl group and a terminal carboxylic acid. This unique design enables sequential conjugation strategies for precisely attaching two distinct molecules (such as drugs and targeting ligands) in controlled orientations. Key advantages include flexible orthogonal reactivity, tunable spacer length (n), and significant solubility enhancement for biomolecules. It should be noted that the hydroxyl group generally requires appropriate activation for efficient covalent conjugation.