Cascade kinetics in an enzyme-loaded aqueous two-phase system

Pavlovic, M., Plucinski, A., Zhang, J., Antonietti, M., Zeininger, L. and Schmidt, B. V. K. J. (2020) Cascade kinetics in an enzyme-loaded aqueous two-phase system. Langmuir, 36(6), pp. 1401-1408. (doi: 10.1021/acs.langmuir.0c00186) (PMID:31977224)

Abstract

Macromolecular crowding plays a critical role in the kinetics of enzymatic reactions. Dynamic compartmentalization of biological components in living cells due to liquid–liquid phase separation represents an important cell regulatory mechanism that can increase enzyme concentration locally and influence the diffusion of substrates. In the present study, we probed partitioning of two enzymes (horseradish-peroxidase and urate-oxidase) in a poly(ethylene glycol)–dextran aqueous two-phase system (ATPS) as a function of salt concentration and ion position in the Hofmeister series. Moreover, we investigated enzymatic cascade reactions and their kinetics within the ATPS, which revealed a strong influence of the ion hydration stemming from the background electrolyte on the partitioning coefficients of proteins following the Hofmeister series. As a result, we were able to realize cross-partitioning of two enzymes because of different protein net charges at a chosen pH. Our study reveals a strong dependency of the enzyme activity on the substrate type and crowding agent interaction on the final kinetics of enzymatic reactions in the ATPS and therefore provides substantial implications en route toward dynamic regulation of reactivity in synthetic protocells.

• Item Type: Articles
• Additional Information: The authors are grateful for funding from the Max-Planck society. M.P. acknowledges financial support from the Swiss National Science Foundation with the project number P2GEP2_181528. B.S. and A.P. acknowledge funding from the University of Glasgow and the German Research Foundation (grant no. SCHM 3282/3-1). J.Z. acknowledges funding from the China Scholarship Council. L.Z. is grateful for funding through the Emmy-Noether program of the German Research Foundation (grant no. ZE 1121/3-1).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Plucinski, Alexander and Schmidt, Dr Bernhard
• Authors: Pavlovic, M., Plucinski, A., Zhang, J., Antonietti, M., Zeininger, L., and Schmidt, B. V. K. J.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Langmuir
• Publisher: American Chemical Society
• ISSN: 0743-7463
• ISSN (Online): 1520-5827
• Published Online: 24 January 2020
• Copyright Holders: Copyright © 2020 American Chemical Society
• First Published: First published in Langmuir 36(6): 1401-1408
• Publisher Policy: Reproduced under a Creative Commons License