Linear Eyring plots conceal a change in rate-limiting step in an enzyme reaction
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The temperature dependence of psychrophilic and mesophilic (R)-3-hydroxybutyrate dehydrogenase steady-state rates yields nonlinear and linear Eyring plots, respectively. Solvent viscosity effects and multiple- and single-turnover pre-steady-state kinetics demonstrate that while product release is rate-limiting at high temperatures for the psychrophilic enzyme, either interconversion between enzyme-substrates and enzyme-products complexes or a step prior to it limits the rate at low temperature. Unexpectedly, a similar change in rate-limiting step is observed with the mesophilic en-zyme, where a step prior to chemistry becomes rate-limiting at low temperature. This observation may have implica-tions for past and future interpretation of temperature-rate profiles.
Machado , T F G , Gloster , T & da Silva , R G 2018 , ' Linear Eyring plots conceal a change in rate-limiting step in an enzyme reaction ' Biochemistry , vol. 57 , no. 49 , pp. 6757-6761 . DOI: 10.1021/acs.biochem.8b01099
© 2018 American Chemical Society. This is an open access article published under a Creative Commons Attribution (CC-BY) License, which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited.
DescriptionThis work was supported by the Engineering and Physical Sciences Research Council (EPSRC) [grant number EP/L016419/1] via a CRITICAT Centre for Doctoral Training studentship to T.F.G.M. T.M.G. is a Wellcome Trust Career Development Fellow.
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