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Bis-sulfone PEG contains a bis-sulfone group and a polyethylene glycol (PEG) moiety. The bis-sulfone compound is a highly reactive bis-alkylation reagent. It readily react with two cysteine thiols that is derived from reduction of the disulfide bridge on protein/antibody to form site specific conjugation. The ADCs using bis-sulfone PEG linkers shows superior homogeneity and improved solubility, biocompatibility, and stability.

For example, the clinical stage drug candidate OBI-999 is derived from conjugation of the GH-targeting mAb OBI-888 with MMAE through a ThioBridge and a protease cleavable peptide-based linker. The linker contains a valine-citrulline-p-aminobenzyl (PAB) system to ensure stability in the bloodstream and specific cleavage by cathepsin B after internalization. The bis-sulfone functionalized drug linker was site-specifically attached to OBI-888 by cross-linking to the reduced cysteines in the Fab and hinge regions of the antibody to form Thiobridges. OBI-999 exhibited excellent homogeneity with a DAR of 4 (>95%), while other ADCs have wide range of DAR from of 1 to 8. PEG24 linked to the glutamic acid in the linker is used to reduce the hydrophobicity of OBI-999. Compared with currently approved ADCs, OBI-999 is more homogenous and more stable than ADCs that utilize a maleimide linker.*

Thiobridges in the controlled site specific conjugation afford homogenous ADC (DAR = 4)

Bis-sulfone alkylating labeling involves two steps: 1. disulfide reduction to release the two cysteine thiols and 2. re-forming a three-carbon bridge by bis-alkylation to which other functional group is covalently attached. This process avoids the potential irreversible denaturation of the proteins by maintaining their tertiary structure. This bis-sulfone approach, together with the dibromo-maleimide approach, offers biologists a great tool for site specific bioconjugation that impairs no or least biological activities.

The PEG-bis-sulfone can also undergoes site-specific conjugation to the histidines in C or N-terminal tag without metal chelation. The site selective PEGylation between the poly-histidine tag (His-tag) bearing protein and PEG-bis-sulfone through a bis-alkylation process represents a promising conjugation approach that retains the  biological activity after protein modification/purification.*



Cat# Name Structure M.W. Purity Pricing
Bis-sulfone Amine
AP12594Bis-sulfone Amine593.15 (HCl salt)≥95% Pricing
Bis-sulfone NHS Ester
AP12583Bis-sulfone NHS Ester597.66≥95% Pricing
AP13034Bis-sulfone-PEG4-NHS ester844.95≥95% Pricing
AP13386Bis-sulfone-PEG8-NHS Ester1021.2≥95% Pricing
AP13387Bis-sulfone-PEG12-NHS Ester1197.4≥90% Pricing
AP12582Bis-sulfone Acid500.58≥95% Pricing
AP13036Bis-sulfone-PEG4-acid747.87≥95% Pricing
AP13037Bis-sulfone-PEG8-acid924.08≥95% Pricing
AP13446Bis-sulfone-PEG12-Acid1100.3≥98% Pricing
AP13033Bis-sulfone-PEG3-azide700.83≥95% Pricing
AP13035Bis-sulfone-sulfo-PEG3-azide822.97≥95% Pricing
AP13143Bis-sulfone-PEG3-Biotin901.12≥95% Pricing
AP12593Bis-sulfone-PEG4-DBCO1006.19≥95% Pricing
AP13193Bis-Sulfone-PEG9-DBCO1226.5≥96% Pricing
AP13032Bis-sulfone-PEG4-m689.84≥95% Pricing
AP13038Bis-sulfone-PEG24-m1570.895≥95% Pricing
AP13141Bis-sulfone-PEG4-methyl-tetrazine845.98≥95% Pricing
AP14229Bis-sulfone-PEG4-TCO871.10≥95% Pricing

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