dc.contributor.author | Roy, Alexander C | |
dc.date.accessioned | 2015-04-28T15:00:23Z | |
dc.date.available | 2015-04-28T15:00:23Z | |
dc.date.issued | 2015-04-28 | |
dc.identifier.uri | http://hdl.handle.net/10222/56647 | |
dc.description.abstract | Low temperatures impose a unique set of restrictions on the thermodynamic strategies available for enzymatic catalysis. The specific thermodynamic consequences of cold environments were determined for two psychrophile-derived variants of the highly-proficient enzyme, orotidine 5?–monophosphate decarboxylase (ODCase) — one from Psychrobacter arcticus 273–4 (PaODCase), and another from Colwellia psychrerythraea 34H (CpODCase). Determination of the kinetic parameters of these psychrozymes as a function of temperature indicated that PaODCase operates through entropy-driven ground-state-destabilisation, while CpODCase operates primarily through enthalpy-driven transition-state-stabilisation. In the context of prior studies conducted with mesozyme and thermozyme ODCase-variants, a large value of kcat was found to be the most consistent hallmark of a psychrozyme. Interestingly, a low value of an enzyme's melting temperature (Tm) appeared to correlate weakly with low-temperature activity. On the whole, the trends identified herein afford greater understanding of the unique challenges to providing catalysis at low-temperatures overcome by psychrozymes. | en_US |
dc.language.iso | en | en_US |
dc.subject | Orotidine 5′-monophosphate decarboxylase, extremophile, psychrophile, mesophile, thermophile, ODCase, enzymology, biochemistry, thermodynamics, catalysis | en_US |
dc.title | CATALYSIS BY EXTREMOZYMES: COMPARING OROTIDINE 5?- MONOPHOSPHATE DECARBOXYLASES FROM PSYCHROPHILES, MESOPHILES, AND THERMOPHILES | en_US |
dc.date.defence | 2013-03-26 | |
dc.contributor.department | Department of Chemistry | en_US |
dc.contributor.degree | Master of Science | en_US |
dc.contributor.external-examiner | n/a | en_US |
dc.contributor.graduate-coordinator | Mark Stradiotto | en_US |
dc.contributor.thesis-reader | David Jakeman, Donald Weaver, Frances L Cozens | en_US |
dc.contributor.thesis-supervisor | Stephen L Bearne | en_US |
dc.contributor.ethics-approval | Not Applicable | en_US |
dc.contributor.manuscripts | Not Applicable | en_US |
dc.contributor.copyright-release | Not Applicable | en_US |