Related Experiment Video
Updated: Sep 24, 2025

Genetic Encoding of a Non-Canonical Amino Acid for the Generation of Antibody-Drug Conjugates Through a Fast Bioorthogonal Reaction
Published on: September 14, 2018
Cysteine metabolic engineering and selective disulfide reduction produce superior antibody-drug-conjugates
Renée Procopio-Melino1, Frank W Kotch2, Amar S Prashad3,4
1BioProcess R&D, Biotherapeutics Pharmaceutical Sciences, Medicinal Sciences, Pfizer Worldwide R&D, 1 Burtt Road, Andover, MA, 01810, USA.
Abstract:
Next-generation site-specific cysteine-based antibody-drug-conjugates (ADCs) broaden therapeutic index by precise drug-antibody attachments. However, manufacturing such ADCs for clinical validation requires complex full reduction and reoxidation processes, impacting product quality. To overcome this technical challenge, we developed a novel antibody manufacturing process through cysteine (Cys) metabolic engineering in Chinese hamster ovary cells implementing a unique cysteine-capping technology. This development enabled a direct conjugation of drugs after chemoselective-reduction with mild reductant tris(3-sulfonatophenyl)phosphine. This innovative platform produces clinical ADC products with superior quality through a simplified manufacturing process. This technology also has the potential to integrate Cys-based site-specific conjugation with other site-specific conjugation methodologies to develop multi-drug ADCs and exploit multi-mechanisms of action for effective cancer treatments.
Related Concept Videos
Drug Metabolism: Phase II Reactions
Phase II Reactions: Sulfation and Conjugation with α-Amino Acids
Sulfur Assimilation
Phase II Reactions: Miscellaneous Conjugation Reactions
A key example involves the conjugation of cyanide ions, which impair cellular respiration and alter hemoglobin into non-oxygen-carrying cyanmethemoglobin. To neutralize this threat, a sulfur atom from thiosulphate is transferred to the cyanide ion, catalyzed by the enzyme rhodanese, resulting in an inactive compound called thiocyanate. The production of...

