Currently, antibodies are widely
used not only in research but
also in therapy. Hence, peptides that selectively bind to the fragment
crystallizable site of an antibody have been extensively utilized
in various research efforts such as the preparation of antibody–drug
conjugates (ADC). Consequently, appropriate peptides that bind to
immunoglobulin G (IgG) with a specific Kd value and also kon and koff values will be useful in different applications, and
these kinetic parameters have been perhaps overlooked but are key
to development of peptide ligands with advantageous binding properties.
We prepared structural derivatives of IgG-binding peptide 1 and evaluated the binding affinity and kinetic rates of the products
by surface plasmon resonance assay and isothermal titration calorimetry
to obtain novel peptides with beneficial antibody binding properties.
In this way, 15-Lys8Leu with fast-binding and slow-release
features was obtained through a shortened peptide 15-IgBP. On the
other hand, we successfully obtained distinctive peptide, 15-Lys8Tle, with a similar Kd value but with kon and koff values
that were as much as six-fold different from those of 15-IgBP. These
new peptides are useful for the elucidation of kinetic effects on
the function of IgG-binding peptides and various applications of antibody
or antibody–drug interactions, such as immunoliposome, ADC,
or half-life extension strategy, by using a peptide with the appropriate
kinetic features.