We were awarded a Marsden Council grant (2020) to continue testing a new theory of temperature response of biological systems called macromolecular rate theory (MMRT). We work in close collaboration with Vic Arcus who originally proposed the approach based on ideas tracing back to 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.
We have recently proposed that the Tinf of enzyme is critical for determining the upper growth temperature or organisms called the inflection point hypothesis.
Some key papers 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.