Arrhenius plots presenting the temperature dependences of the natural logarithm (LN) of kinetic parameters k_ACT (A), k_LIN (B), t_LIN⁻¹ (C), and k_REL (D) for cardiac myofibrils isolated from adult zebrafish; the energies of activation (E_a, indicated in figures) are calculated from slopes of the linear regressions (Eq. 3) and can be compared with E_a corresponding to murine cardiac myofibrils: E_a = 72 kJ/mol for k_ACT, E_a = 61 kJ/mol for t_LIN⁻¹, and E_a = 57 kJ/mol for k_REL (murine data taken from Stehle et al., 2002).