A temperature-induced transition in mitochondrial oxidation: Contrasts between cold and warm-blooded animals

• 1.

  1. Arrhenius plots for succinate oxidation by mitochondria from homeothermic animals indicate a phase change at approximately 23°C with an increased activation energy below this transition temperature.

• 2.

  2. Similar plots for poikilotherms are continuous and linear with no change in activation energy over the entire range from 4–30°C.

• 3.

  3. These results are suggested to be related to a direct response to temperature causing a configurational change of the membrane associated enzyme proteins induced by a phase change in the membrane lipids in homeotherms not observed in poikilotherms.