Insertion of a Flexible Spacer Increases the Yield of Site-Specific Bioconjugation through N-Terminal Transamination

Background: Recently, several chemoselective techniques have been developed to modify biomolecules at a single site. Among these, biomimetic transamination reaction through pyridoxal-5- phosphate is able exclusively to convert the N-terminus of protein/peptides into a ketone/aldehyde under mild conditions. The ketone/aldehyde group can be conjugated with another biomolecule, for example, with an aminooxy group via oxime formation. Keywords: Chemoselective ligation, oxime, peptide, spacer, transamination, α-ketoaldehyde.