Changes in Succinyl CoA Synthetase Activity in Etiolated Bean Leaves Caused by Illumination

The illumination of etiolated bean leaves (Phaseolus vulgaris) causes an increase in the activity of succinyl coenzyme A synthetase. Continuous white light or short periods of red or blue light followed by darkness will induce an increase with the highest activity at about 6 hr after the onset of illumination. Thereafter the activity decreases so that at 12 hr it is the same as the initial dark activity. Treatment with cycloheximide before illumination prevents the increase in activity. A number of other enzymes have been studied in an attempt to determine the significance of the transient nature of the changes in succinyl CoA synthetase activity.