Photoconversion of protochlorophyll to chlorophyll a in a mutant of Chlorella regularis

Dark-grown cells of a mutant strain of Chlorella regularis containedchlorophyll a and protochlorophyll, phytyl ester of protochlorophyllide.Under illumination, protochlorophyll was quantitatively anddirectly converted into chlorophyll a. The photoconversion wasdependent on light intensity and temperature and proceeded ina cell-free preparation. The pathway of chlorophyll formation found in the mutant cellsis entirely different from that from protochlorophyllide byway of chlorophyllide a, which is generally observed in greenplants. ¹Present address: Division of Biology, Medical College of Miyazaki,Miyazaki 889-16, Japan. ²Present address: Division of Environmental Biology, The NationalInstitute for Environmental Studies, Ibaragi 300-21, Japan. (Received October 24, 1975; )