New bile pigment excreted by a Chlamydomonas reinhardtii mutant: A possible breakdown catabolite of chlorophyll a

A chlorophyll b-less mutant of Chlamydomonas reinhardtii excreted new red pigments into the medium accompanying degreening of cells during growth. Accumulation of red pigments in the medium and disappearance of chlorophyll a in algal cells were closely related. A major component (P535) was purified by reversed-phase chromatograph): and showed absorption maxima at 535, 385, and 275 nm with shoulders at 570, 500, and 320 nm. Analysis of degradation products by chromic oxidation, together with spectroscopic properties and molecular-mass determination, indicated that P535 Lore a structural resemblance to bile pigments characterized by an open tetrapyrrole. It is suggested that the red pigments are probably derived from chlorophyll a.