The Kinetics of Isocitrate Lyase Formation inChlorella: Evidence for the Promotion of Enzyme Synthesis by Photophosphorylation

Publisher Website
Google Scholar
Abstract
The addition of acetate to aerobic Chlorella pyrenoidosa in darkness was followed by the formations of isocitrate lyase actiity. After a lag period of 40 minutes the formation proceeded at a constant rate. By use of actylamide gel electrophoresis it was shown that the increase in enzyme activity was accompanied by the formation of a new protein which, after separation by electrophoresis, contained isocitrate lyase activity. The formation of isocitrate lyase was repressed by glucose; it was repressed by light in the presence of carbon dioxide, but not when DCMU was added. In light, plus DCMU, isocitrate lyase was formed anaerobically and the capacity for photo-formation of isocitrate lyase was saturated at 500 ergs/cm2/sec. In this respect the process resembled the photo-conversion of glucose to polysaccharide but differed from the photo-assimilation of carbon dioxide which became saturated at a heigher light intensity. Monochromatic light of 706 mμ wavelength supported both isocitrate layse formation and the conversion of glucose to polysaccharide but not carbon dioxide fixation. It is concluded that ATP generated by cyclic photophosphorylatin can provide the energy for isocitrate lyase synthesis in Chlorella.

This publication has 2 references indexed in Scilit: