Pegylation of protein or peptide at their N-terminus amino groups have advantages over radom pegylation. Bioactivity of N-terminal pegylated biomolecules will be retained better compared to random lysine pegylation. Nanocs now offers a number of novel aldehyde PEG reagents that allow N-terminus amine Pegylation at low pH (pH 5.0-6.5). Nanocs provides various aldehyde PEG derivatives which include methoxy PEG aldehyde with different molecular weight, lipid PEG aldehyde, phospholipid PEG aldehyde, fluorescent PEG aldehyde, biotin PEG aldehyde and many other aldehyde PEG derivatives.