S1-5 Thursday, Jan. 5 10:30 - 11:00 The combined effects of reactant kinetics and enzyme stability explain the temperature dependence of metabolic rates DELONG, John/P*; GIBERT, Jean/P; LUHRING, Tom/M; BACHMAN, Gwendolyn; REED, Benjamin; NEYER, Abigail; MONTOOTH, Kristi/M; University of Nebraska - Lincoln email@example.com
A mechanistic understanding of the response of metabolic rate to temperature is essential for understanding thermal ecology and metabolic adaptation. While the Arrhenius equation has been used to describe the effects of temperature on reaction rates and metabolic traits, it does not adequately describe two aspects of the thermal performance curve (TPC) for metabolic rate – that metabolic rate is a unimodal function of temperature often with maximal values in the biologically relevant temperature range and that activation energies are temperature dependent. Here we show that the temperature dependence of metabolic rate in ectotherms is well described by an enzyme-assisted Arrhenius (EAAR) model that accounts for the temperature-dependent contribution of enzymes to decreasing the activation energy required for reactions to occur. The model is mechanistically derived using the thermodynamic rules that govern protein stability and yields biologically meaningful parameters. By fitting the model to available datasets we demonstrate its utility in generating predictions about how metabolic rates acclimate and adapt to changes in thermal environment.