Skip to main content
  • Poster presentation
  • Open access
  • Published:

Molecular modeling studies of lipase-catalyzed β-lactam polymerization

Enzymatic polymerization has emerged over the last 5 years as a field of considerable interest and commercial promise. The reaction proceeds with high regio-, enantio-, and chemoselectivity under relatively mild conditions. Enzymes have been used so far to synthesize polyesters, polysaccharides, polycarbonates, polyphenols, polyanilines, vinyl polymers, and poly-amino acids [1]. Particularly, lipase B of Candida antarctica immobilized on polyacrylic resin (Novozyme 435) has proven to be a very versatile catalyst and has successfully been used for the synthesis of polyesters from various substrates [2][3][4]. Little, however, has been reported on the enzyme catalyzed synthesis of polyamides [5].

While it has been shown that nylons can chemically be produced from the corresponding amino acids or by anionic ring-opening polymerization of 5–13 membered unsubstituted lactams, poly-β-alanine has not yet been obtained by either polymerization of β-alanine or β-lactam (2-azetidinone). Using lipase B of Candida antarctica we have recently been successful in the production of unbranched poly-βalanine starting from unsubstituted β-lactam [6].

Here we report preliminary molecular modeling studies of the lipase catalyzed ringopening polymerization of β-lactam towards an understanding of the underlying enzymatic mechanism. We can show that amide formation initially follows the well-known enzymatic acylation of Ser105 by β-lactam using Asp187 and His224 of the catalytic centre and Thr40 and Gly106 as oxy-anion hole. The elongation of the chain, however, utilizes different parts of the active site. The mechanism is only applicable for β-lactam and can not be utilized by β-alanine and suggests a reasoning for the experimental finding that β-alanine can not be polymerized enzymatically but rather inhibits the polymerization in a copolymerization experiment with β-lactam and β-alanine.


  1. Kobayashi S, Ritter H, Kaplan D, eds: Enzyme-Catalyzed Synthesis of Polymers (Advances in Polmyer Science). 2007, Springer, Berlin

    Google Scholar 

  2. Thurecht KJ, Heise A, deGeus M, Villarroya S, Zhou JX, Wyatt MF, Howdle SM: Macromolecules. 2006, 39: 7967-10.1021/ma061310q.

    Article  CAS  Google Scholar 

  3. Mee van der L, Helmich F, de Bruijn R, Vekemans JAJM, Palmans ARA, Meijer EW: Macromolecules. 2006, 39: 5021-10.1021/ma060668j.

    Article  Google Scholar 

  4. Kumar A, Mei Y, Gross R: Macromolecules. 2003, 36: 5530-10.1021/ma025741u.

    Article  Google Scholar 

  5. Gu Q-M, Maslanka WW, Cheng HN: Polym Prepr. 2006, 4: 234-

    Google Scholar 

  6. Schwab LW, Kroon R, Schouten AJ, Loos K: Macromol Rapid Commun. 2008, 29: 794-797. 10.1002/marc.200800117.

    Article  CAS  Google Scholar 

Download references

Author information

Authors and Affiliations


Rights and permissions

Open Access This article is distributed under the terms of the Creative Commons Attribution 2.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Reprints and permissions

About this article

Cite this article

Baum, I., Haller, L., Schwab, L. et al. Molecular modeling studies of lipase-catalyzed β-lactam polymerization. Chemistry Central Journal 3 (Suppl 1), P57 (2009).

Download citation

  • Published:

  • DOI: