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Smart PEGylation of Trypsin

: Zarafshani, Z.; Obata, T.; Lutz, J.-F.


Biomacromolecules 11 (2010), No.8, pp.2130-2135
ISSN: 1525-7797
Journal Article
Fraunhofer IAP ()

Thermoresponsive oligo(ethylene glycol)-based copolymers were investigated for trypsin conjugation. These copolymers have been synthesized by atom transfer radical polymerization of 2-(2-methoxyethoxy)ethyl methacrylate (MEO2MA) with oligo(ethylene glycol) methyl ether methacrylate (OEGMA475, Mn = 475 g·mol-1) at 60 °C in the presence of copper(I) chloride and 2,2'-bipyridyl. Two different ATRP initiators, containing succinimidyl ester moieties, were tested, namely, N-succinimidyl-2-bromopropionate and N-succinimidyl-2-bromoisobutyrate. In both cases, ATRP afforded well-defined polymers with a narrow molecular weight distribution and controlled chain-ends. However, the efficiency of initiation of the two initiators was lower than 1 and therefore the formed polymers exhibited a higher than expected mean degree of polymerization. Nevertheless, all types of polymers could be conjugated to trypsin. The conjugation reaction was performed in borax-HCl buffer. Sodium dodecyl sulfate poly(acrylamide) gel electrophoresis (SDS-PAGE) indicated that polymer/enzyme conjugates were obtained in all cases. However, (co)polymers initiated by N-succinimidyl-2-bromopropionate led to the best conjugation results. The formed P(MEO2MA-co-OEGMA475)-trypsin conjugates were found to be thermoresponsive and moreover exhibited a higher enzymatic activity than unmodified trypsin.