The Influence of 5-Aminolevulinic Acid on Protochlorophyllide and Protochlorophyll Accumulation in Dark-Grown Scenedesmus

The interm ediate o f chlorophyll b iosynthesis, 5-am inolevulinic acid (A L A ), is a necessary prerequisite for the form ation o f protochlorophyllide (PChlide) and protochlorophyll (PChl) in the dark. The application o f A L A to a dark-grown culture o f the pigm ent m utant C-2 A' o f Scenedesmus obliquus increased the am ount o f PChlide 30-fold and the am ount o f PChl about 10-fold. The rates o f A L A -dependent form ation o f PChlide and PChl reach their m axim um values at different concentrations o f added A L A . Sim ilarly, the kinetics o f PChlide and PChl form ation in cells incubated with A L A are different. Cells o f Scenedesmus m utant C-2 A' incu­ bated with various concentrations o f A L A for different periods provide a good tool for future studies differentiating between PChlide and PChl m etabolism . — The incorporation o f Chi de­ riving from either PChl or PChlide into different pigm ent protein com plexes is discussed.