Lipolytic Enzymes with Improved Activity and Selectivity upon Adsorption on Polymeric Nanoparticles

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• 作者：Cleofe Palocci ; Laura Chronopoulou ; Iole Venditti ; Enrico Cernia ; Marco Diociaiuti ; Ilaria Fratoddi ; Maria Vittoria Russo
• 刊名：Biomacromolecules
• 出版年：2007
• 出版时间：October 2007
• 年：2007
• 卷：8
• 期：10
• 页码：3047 - 3053
• 全文大小：422K
• 年卷期：v.8,no.10(October 2007)
• ISSN：1526-4602

文摘

Nanostructured polystyrene (PS) and polymethylmethacrylate (PMMA) were used as carriers for the preparationof bioconjugates with lipolytic enzymes, such as Candida rugosa lipase (CRL) and Pseudomonas cepacia lipase(PCL). Simple addition of the lipase solution to the polymeric nanoparticles under protein-friendly conditions(pH 7.6) led to the formation of polymer-enzyme bioconjugates. Energy filtered-transmission electron microscopy(EF-TEM) performed on immuno-gold labeled samples revealed that the enzyme preferentially binds to the polymernanoparticles and that the binding does not affect the nanostructured features of the carriers. The studies performedon the activity of the bioconjugates pointed out that the lipases adsorbed onto polymeric nanoparticles show animproved performance in terms of activity and selectivity with respect to those shown by lipases adsorbed on thesame non-nanostructured carriers. The residual activities of CRL and PCL immobilized on nanostructured PMMAand PS reached 60% and 74%, respectively. Moreover, we found that enantioselectivity and pH and thermalstability increase upon immobilization. These results highlight the fact that new protein conformers with improvedenantioselectivity stabilized after adsorption on nanoparticles are obtained. On the basis of the chemical structuresof the selected polymers and the slopes of the adsorption isotherms, a hydrophobic binding model for lipase/nanostructured polymers is suggested.