6533b7d2fe1ef96bd125df76

RESEARCH PRODUCT

Poly(S-ethylsulfonyl-l-cysteines) for Chemoselective Disulfide Formation

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description

The amino acid cysteine possesses a unique role in nature due to its ability to reversibly cross-link proteins. To transfer this feature to polypeptides and control the process of disulfide formation, a protective group needs to provide stability against amines during synthesis, combined with chemoselective reactivity toward thiols. A protective group providing these unique balance of stability and reactivity toward different nucleophiles is the S-alkylsulfonyl group. In this work we report the polymerization of S-ethylsulfonyl-l-cysteine N-carboxyanhydride and kinetic evaluations with respect to temperature (−10, 0, and +10 °C) and monomer concentration. The polymerization degree of poly(S-ethylsulfonyl-l-cysteines) can be controlled within a range of 10–30, yielding well-defined polymers with molecular weights of 6900–12 300 g/mol with dispersity indices of 1.12–1.19 as determined by GPC and MALDI–TOF analysis. The limitation of chain length is, however, not related to side reactions during ring-opening...