PEG-chitosan branched copolymers to improve the biocatalytic properties of erwinia carotovora recombinant L-asparaginase

Kudryashova E.V.1 , Suhoverkov K.V.1, Sokolov N.N.2

1. Moscow State University, Moscow, Russia
2. Institute of Biomedical Chemistry, Moscow, Russia
Section: Experimental/Clinical Study
DOI: 10.18097/PBMC20156104480      PubMed Id: 26350739
Year: 2015  Volume: 61  Issue: 4  Pages: 480-487
A new approach to the regulation of catalytic properties of medically relevant enzymes has been proposed using the novel recombinant preparation of L-asparaginase from Erwinia carotovora (EwA), a promising antitumor agent. New branched co-polymers of different composition based on chitosan modified with polyethylene glycol (PEG) molecules, designated as PEG-chitosan, have been synthesized. PEG-chitosan copolymers were further conjugated with EwA. In order to optimize the catalytic properties of asparaginase two types of conjugates differing in their architecture have been synthesized: (1) crown-type conjugates were synthesized by reductive amination reaction between the reducing end of the PEG-chitosan copolymer and enzyme amino groups; (2) multipoint-conjugates were synthesized using the reaction of multipoint amide bond formation between PEG-chitosan amino groups and carboxyl groups of the enzyme in the presence of the Woodward’s reagent. The structure and composition of these conjugates were determined by IR spectroscopy. The content of the copolymers in the conjugates was controlled by the characteristic absorption band of C-O-C bonds in the PEG structure at the frequency of 1089 cm-1. The study of catalytic characteristics of EwA preparations by conductometry showed that at physiological pH values the enzyme conjugates with PEG-chitosan with optimized structure and the optimal composition demonstrated 5-8-fold higher catalytic efficiency (kcat/Km) than the native enzyme. To certain extent, this can be attributed to favorable shift of pH-optima in result of positively charged amino-groups introduction in the vicinity of the active site. The proposed approach, chito-pegylation, is effective for regulating the catalytic and pharmacokinetic properties of asparaginase, and is promising for the development of prolonged action dosage forms for other enzyme therapeutics
Download PDF:  
Keywords: L-asparaginase, PEG-chitosan, branched copolymers, catalytic activity, conductometry, IR spectroscopy

Kudryashova, E. V., Suhoverkov, K. V., Sokolov, N. N. (2015). PEG-chitosan branched copolymers to improve the biocatalytic properties of erwinia carotovora recombinant L-asparaginase. Biomeditsinskaya Khimiya, 61(4), 480-487.
This paper is also available as the English translation: 10.1134/S1990750814030081
 2024 (vol 70)
 2023 (vol 69)
 2022 (vol 68)
 2021 (vol 67)
 2020 (vol 66)
 2019 (vol 65)
 2018 (vol 64)
 2017 (vol 63)
 2016 (vol 62)
 2015 (vol 61)
 2014 (vol 60)
 2013 (vol 59)
 2012 (vol 58)
 2011 (vol 57)
 2010 (vol 56)
 2009 (vol 55)
 2008 (vol 54)
 2007 (vol 53)
 2006 (vol 52)
 2005 (vol 51)
 2004 (vol 50)
 2003 (vol 49)