Temperature response of biological systems

Vic and Louis before WaiBOP conference

Vic and Louis before WaiBOP conference

We are testing a new theory of temperature sensitivity of biological systems called macromolecular rate theory (MMRT). Vic Arcus has led this work and a key collaborator. He built on the equations originally developed by Arrhenius and Gibbs to capture the importance of the enzyme’s heat capacity to predict rates of enzyme-catalysed reactions. Together we have been testing how well MMRT is able to capture temperature response of enzyme, microbes, soil processes, leaf respiration and ecosystem response.

A recent presentation on the implications for soil biogeochemistry by Louis can be found here and an overview of the implications of the theory more generally is summarised in the paper here.

MMRT works very well – predicting a temperature optimum for enzyme activity without requiring denaturation. MMRT also allows determination of Tinf – the temperature at  which the temperature sensitivity is maximal, i.e., when the rate of change in activity is maximal for a change in temperature.

The MatLab code for fitting MMRT is here.

Some key paper to date:

Schipper, L.A.; Hobbs, J.K.; Rutledge S.; Arcus, V.L. (2014) Thermodynamic theory explains the temperature optima of soil microbial processes and High Q10 Values at Low Temperatures. Global Change Biology. DOI: 10.1111/gcb.12596

Arcus, V.L.; Prentice, E.; Hobbs, J.K.; Mulholland, A.J.; Vander Kamp, M.W.; Pudney, C.R.; Parker, E.J.; Schipper, L.A. (2016) On the temperature dependence of enzyme-catalysed rates. Biochemistry. 55: 1681-1688. ACS Editors’ Choice

Hobbs, J.K.; Jiao, W.; Easter, A.D.; Parker, E.J.; Schipper, L.A.; Arcus, V.L. (2013) The Change in Heat Capacity for Enzyme Catalysis Determines the Temperature Dependence of Enzyme Catalysed Rates. ACS Chemical Biology. 8: 2388-2393.

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