Cysteine Conjugation | Abzena

Cysteine Conjugation

  • Maximum of 8 possible conjugation sites
  • Choice of engineered cysteines, Maleimide, Haloacetyle or CyPEG™ conjugation options

Abzena can selectively reduce the interchain disulfide bonds of an antibody creating sulfhydryl groups which are available for conjugation, while leaving intrachain disulfides intact. Using this strategy of cysteine-based conjugation, the antibody is first treated with reducing agents, such as dithiothreitol (DTT) or tris (2-carboxyethyl) phosphine (TCEP), to convert the interchain disulfides to free cysteine residues. The free sulfhydryl (SH) groups of the antibody can then be conjugated with thiol-reactive linkers such as maleimide-containing linkers to form ADCs which are heterogeneous mixtures of ADC species, each containing 0-8 drugs per antibody (DAR≤8). This is an effective strategy that does not require expensive and time-consuming re-engineering of the antibody structure.

CyPEG™ – Cysteine conjugation

CyPEG™ is Abzena’s proprietary conjugation technology for site-specific conjugation at a sulfhydryl group of a free cysteine. The thiol residue on a cysteine readily undergoes selective and efficient conjugation. CyPEG™ can be used over a wide pH range and results in a more stable conjugate than can be produced using maleimide conjugation chemistry.

Engineered Cysteines

Abzena can engineer unpaired cysteine residues on each heavy chain to then be used for conjugation with thiol thiol-reactive linkers to create more homogeneous ADCs with a drug to antibody ratio of two. Abzena has considerable experience in producing ADCs by this approach.

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Abzena’s services are tailored for each project to ensure that the objectives are met or exceeded. Experienced project teams are assigned to each study focusing on progressing projects through to results in the minimum amount of time. Our clients widely regard us as professional and attentive partners who deliver quality results.

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