Optimization of Poly(N‑isopropylacrylamide) as an Artificial Amidase

• Published in: Biomacromolecules 2015-01, Vol.16 (1), p.411-421
• Main Authors: Wong, Yoke-Ming, Hoshino, Yu, Sudesh, Kumar, Miura, Yoshiko, Numata, Keiji
• Format: Article
• Language: English
• Subjects: Acrylic Resins - chemistry; Amidohydrolases - chemistry; Biomimetic Materials - chemistry; Hydrogels - chemistry; Hydrogels - metabolism; Hydrolysis; Hydrophobic and Hydrophilic Interactions; Kinetics
• ISSN: 1525-7797; 1526-4602
• DOI: 10.1021/bm501671r

Poly(N-isopropylacrylamide) microgel (NMG) has been developed by adding various functional groups to control surface charges, hydrophobicity, pK a and protein adsorption capacity. Here, we developed and optimized NMG anchored with three types of functional groups as a polymeric catalyst to hydrolyze amide bonds under optimized mild conditions. Various optimization strategies were evaluated for efficient hydrolysis activity on a p-nitroaniline-based substrate by using a colorimetric assay. Based on the results, we propose a mechanism to hydrolyze amide bonds and determine the theoretical average distance, using NMG bearing functional group of 1-vinylimidazole as the study model. The hydrolysis of amide bonds was inhibited by a transition-state protease inhibitor, which also confirmed the proposed reaction model for NMG. These results provide an insight into the strategies developed to functionalize hydrogels through an enzyme-mimic approach for future robust bio- and chemical conversions as well as therapeutic utilities.