Issue 11, 2015

New chemosynthetic route to linear ε-poly-lysine


ε-Poly-lysine (ε-PL) is an uncommon cationic, naturally-occurring homopolymer produced by the fermentation process. Due to its significant antimicrobial activity and nontoxicity to humans, ε-PL is now industrially produced as an additive, e.g. for food and cosmetics. However, the biosynthetic route can only make polymers with a molecular weight of about 3 kDa. Here, we report a new chemical strategy based on ring-opening polymerization (ROP) to obtain ε-PL from lysine. The 2,5-dimethylpyrrole protected α-amino-ε-caprolactam monomer was prepared through cyclization of lysine followed by protection. ROP of this monomer, followed by the removal of the protecting group, 2,5-dimethylpyrrole, ultimately yielded ε-PL with varying molecular weights. The structure of this chemosynthetic ε-PL has been fully characterized by 1H NMR, 13C NMR, and MALDI-TOF MS analyses. This chemosynthetic ε-PL exhibited a similar pKa value and low cytotoxicity as the biosynthetic analogue. Using this new chemical strategy involving ROP without the need for phosgene may enable a more cost effective production of ε-PL on a larger-scale, facilitating the design of more advanced biomaterials.

Graphical abstract: New chemosynthetic route to linear ε-poly-lysine

Supplementary files

Article information

Article type
Edge Article
09 Jul 2015
28 Jul 2015
First published
28 Jul 2015
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2015,6, 6385-6391

New chemosynthetic route to linear ε-poly-lysine

Y. Tao, X. Chen, F. Jia, S. Wang, C. Xiao, F. Cui, Y. Li, Z. Bian, X. Chen and X. Wang, Chem. Sci., 2015, 6, 6385 DOI: 10.1039/C5SC02479J

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