Polypeptides are fascinating bio-based materials for various fields because of their sequential variety which imparts a wide range of physical and physiological properties. Synthesizing polypeptide materials in an eco-friendly way is essential for realizing a forthcoming sustainable society. Chemoenzymatic synthesis using proteases is a green, facile, and atom-economical method to synthesize polypeptides via sequential aminolysis of amino acid esters. The protease-catalyzed polymerization can be applied to various types of polypeptide synthesis including homopolymers, block copolymers, and polypeptides with special structures such as star-shaped and telechelic polypeptides. In addition to proteinogenic amino acids, unnatural amino acids are also available for the chemoenzymatic polymerization, enabling to expand their applications. In this work, we utilized the chemoenzymatic polymerization technique to synthesize terminal functionalized polypeptides for building blocks to construct special polymeric architectures based on polypeptides.<br/>Amino acid derivatives modified with functional groups such as acrylamide and propargyl groups were prepared as a terminal modifier during chemoenzymatic polymerization. Papain was used as enzymatic catalysis and the polymerization of various amino acid esters was carried out in the presence of the terminal modifying additive in aqueous buffer solution. By optimizing the polymerization condition, desired polypeptides were obtained with complete modification by the functional groups at N-terminal. The chemical structures of the polypeptides were confirmed by <sup>1</sup>H NMR spectroscopy and MALDI-TOF mass spectrometry. In the case using an acrylamide modifier, a series of peaks derived from polypeptides with an acryl amide moiety were observed in MALDI-TOF mass spectra, indicating that the N-terminal of polypeptides was successfully functionalized by the additive in one-pot chemoenzymatic synthesis. The terminal-functionalized polypeptides were used for further post-modification or post-polymerization to construct block or graft polypeptides.

One-pot terminal functionalization of polypeptides by protease-catalyzed chemoenzymatic polymerization

2019 Fall National Meeting

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