Structure–Activity Relationship Study of Affinity Peptides for the Fc Site of Human Immunoglobulin G

Immunoglobulin G (IgG)-binding peptides have been widely used in medicinal chemistry, particularly in the preparation of homogeneous antibody-drug conjugates (ADCs). The dissociation constant (K<sub>d</sub>) and kinetic parameters (k<sub>on</sub> and k<sub>off</sub>) are critical determinants of peptide performance in such applications. In this study, we conducted a structure-activity relationship (SAR) analysis of the IgG-binding peptide 15-IgBP, focusing on Asp3, Tyr6, and Thr15, to identify more potent derivatives with favorable binding affinities and kinetic profiles. Peptides with appropriately tuned ionic structures exhibited rapid binding and release properties, whereas hydrophobic substitutions in solvent-exposed regions led to slower dissociation. By integrating these SAR findings, we identified the optimized affinity peptides, IAPG-2 and IAPG-3, with sub-nanomolar binding affinities (K<sub>d</sub> = 0.753 and 0.705 nM, respectively).

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Publication Details

Journal
Chemical and Pharmaceutical Bulletin
Published
2025-12-17
DOI
https://doi.org/10.1248/cpb.c25-00637
Primary Topic
Monoclonal and Polyclonal Antibodies Research
Type
article
Field-Weighted Citation Impact
0.00

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article

Structure–Activity Relationship Study of Affinity Peptides for the Fc Site of Human Immunoglobulin G

Rento Osawa, Akitomo Kobayashi, Hayate Shida, Kyohei Muguruma et al.
Chemical and Pharmaceutical Bulletin
Monoclonal and Polyclonal Antibodies Research
article

Structure–Activity Relationship Study of Affinity Peptides for the Fc Site of Human Immunoglobulin G

Rento Osawa, Akitomo Kobayashi, Hayate Shida, Kyohei Muguruma, Akio Kuroda, Akihiro Taguchi, Atsuhiko Taniguchi, Nana Sato, Mayu Ito, Kentaro Takayama, Akane Fukuda, Satoshi Kishimoto, Yoshio Hayashi, Yuji Ito, Soichiro Harigaya
article en

Abstract

Immunoglobulin G (IgG)-binding peptides have been widely used in medicinal chemistry, particularly in the preparation of homogeneous antibody-drug conjugates (ADCs). The dissociation constant (K<sub>d</sub>) and kinetic parameters (k<sub>on</sub> and k<sub>off</sub>) are critical determinants of peptide performance in such applications. In this study, we conducted a structure-activity relationship (SAR) analysis of the IgG-binding peptide 15-IgBP, focusing on Asp3, Tyr6, and Thr15, to identify more potent derivatives with favorable binding affinities and kinetic profiles. Peptides with appropriately tuned ionic structures exhibited rapid binding and release properties, whereas hydrophobic substitutions in solvent-exposed regions led to slower dissociation. By integrating these SAR findings, we identified the optimized affinity peptides, IAPG-2 and IAPG-3, with sub-nanomolar binding affinities (K<sub>d</sub> = 0.753 and 0.705 nM, respectively).

Chemical and Pharmaceutical BulletinVol. 73(12)
Kagoshima University (JP), Tokyo University of Pharmacy and Life Sciences (JP)
Japan Agency for Medical Research and Development, Japan Society for the Promotion of Science
Openalex Percentile: Top 44%
Monoclonal and Polyclonal Antibodies Research
DOIOpen Access PDFOpenAlex
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Structure–Activity Relationship Study of Affinity Peptides for the Fc Site of Human Immunoglobulin G — Rento Osawa, Akitomo Kobayashi, et al. · Chemical and Pharmaceutical Bulletin (2025) | TGRS Research Map | TGRS