Synthesis of Chlorophyllide b from Protochlorophyllide in Chlamydomonas reinhardtii y-1.

In cells of Chlamydomonas reinhardtii y-1 kept in the dark, 1,7-phenanthroline stimulated the conversion of protochlorophyllide to chlorophyllide b. A membrane fraction was obtained from degreened cells that was active in this conversion only when phenanthroline was present. Untreated cells excreted protochlorophyllide, which was used as substrate for this in vitro reaction. This system may provide a clue to how chlorophyllide b is synthesized in plant cells.