Activity of Membrane-Bound Enzymes of the Respiratory Chain During Adaptation of Fish to Temperature Changes

Abstract

In tissues of the goldfish, Carassius auratus L., acclimated to 5°, 20° and 30°C, the changes in activity of succinate oxidase in red and white muscle and liver are determined. Red muscle activity decreases, liver activity increases, whereas in white muscle a low but constant activity was found. As this enzyme-comples is associated with an annulus of phospholipids in the inner membrane of mitochondria the unsaturation index of the membrane phospholipids in red muscle was found to decrease with increasing temperature. The changes in the component position are given. Whether the membrane fluidity is affected by these changes of the saturation at different temperatures is uncertain, but the effects on the annulus around succinate oxidase are reflected in the measured activity.