Changes of ribulose 1, 5-diphosphate carboxylase level during the processes of degeneration of chloroplasts in Chlorella protothecoides

RuDP carboxylase was active mainly in chloroplasts and PEP carboxylase active principally outside of chloroplasts in Chlorella protothecoides. (2) During the process of chloroplast degeneration in algal cells induced by addition of glucose, the activity of RuDP carboxylase significantly decreased, whereas the activities of PEP-carboxylase -carboxykinase markedly increased. (3) During the process of chloroplast regeneration in `glucose-bleached' algal cells, which contained no detectable amounts of Fraction I protein and showed only traces of RuDP carboxylase activity, a light-dependent development of RuDP carboxylase proceeded almost in parallel with the light-induced formation of chlorophyll. The activities of PEP-carboxylase and -carboxykinase, which were negligibly low in glucose-bleached cells, developed independently of light. (4) Both chloramphenicol and cycloheximide severely inhibited the development of RuDP carboxylase activity. A relatively low concentration of glucose also caused a significant suppression. Under these conditions, chlorophyll formation was inhibited only slightly by chlorophenicol and very strongly by cycloheximide and glucose.