Kinetics of the urea–urease clock reaction with urease immobilized in hydrogel beads
Kinetics of the urea–urease clock reaction with urease immobilized in hydrogel beads
Feedback driven by enzyme catalyzed reactions occurs widely in biology and has been well characterized in single celled organisms such as yeast. There are still few examples of robust enzyme oscillators in vitro that might be used to study nonlinear dynamical behavior. One of the simplest is the urea–urease reaction that displays autocatalysis driven by the increase in pH accompanying the production of ammonia. A clock reaction was obtained from low to high pH in batch reactor and bistability and oscillations were reported in a continuous flow rector. However, the oscillations were found to be irreproducible and one contributing factor may be the lack of stability of the enzyme in solution at room temperature. Here, we investigated the effect of immobilizing urease in thiol-poly(ethylene glycol) acrylate (PEGDA) hydrogel beads, prepared using emulsion polymerization, on the urea–urease reaction. The resultant mm-sized beads were found to reproduce the pH clock and, under the conditions employed here, the stability of the enzyme was increased from hours to days.
Bubanja, Itana Nuša
7aa6bfd0-4514-462e-9314-0ecda88df45b
Bánsági, Tamás
3984187d-60fd-47f2-b6cb-f312dcedadae
Taylor, Annette Fiona
08028a29-428d-4732-b6b1-f7a93389b386
Bubanja, Itana Nuša
7aa6bfd0-4514-462e-9314-0ecda88df45b
Bánsági, Tamás
3984187d-60fd-47f2-b6cb-f312dcedadae
Taylor, Annette Fiona
08028a29-428d-4732-b6b1-f7a93389b386
Bubanja, Itana Nuša, Bánsági, Tamás and Taylor, Annette Fiona
(2017)
Kinetics of the urea–urease clock reaction with urease immobilized in hydrogel beads.
Reaction Kinetics, Mechanisms and Catalysis.
(doi:10.1007/s11144-017-1296-6).
Abstract
Feedback driven by enzyme catalyzed reactions occurs widely in biology and has been well characterized in single celled organisms such as yeast. There are still few examples of robust enzyme oscillators in vitro that might be used to study nonlinear dynamical behavior. One of the simplest is the urea–urease reaction that displays autocatalysis driven by the increase in pH accompanying the production of ammonia. A clock reaction was obtained from low to high pH in batch reactor and bistability and oscillations were reported in a continuous flow rector. However, the oscillations were found to be irreproducible and one contributing factor may be the lack of stability of the enzyme in solution at room temperature. Here, we investigated the effect of immobilizing urease in thiol-poly(ethylene glycol) acrylate (PEGDA) hydrogel beads, prepared using emulsion polymerization, on the urea–urease reaction. The resultant mm-sized beads were found to reproduce the pH clock and, under the conditions employed here, the stability of the enzyme was increased from hours to days.
Text
s11144-017-1296-6
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Accepted/In Press date: 21 October 2017
e-pub ahead of print date: 31 October 2017
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Local EPrints ID: 505652
URI: http://eprints.soton.ac.uk/id/eprint/505652
ISSN: 1878-5190
PURE UUID: af7cc07c-ac49-43d5-be7f-24d5bc2734ac
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Date deposited: 15 Oct 2025 16:42
Last modified: 16 Oct 2025 02:13
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Author:
Itana Nuša Bubanja
Author:
Tamás Bánsági
Author:
Annette Fiona Taylor
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