Chlorophyll catabolism — structures, mechanisms, conversions

• Published in: Journal of Photochemistry & Photobiology, B: Biology B: Biology, 1996-02, Vol.32 (3), p.141-151
• Main Authors: Gossauer, Albert, Engel, Norbert
• Format: Article
• Language: English
• Subjects: Autumnal chlorophyll degradation; Chlorella protothecoides; Chlorophyll catabolism in green algae; Chlorophyll catabolites in a chlorophyte; Chlorophyll catabolites in angiosperms; Linear tetrapyrroles
• ISSN: 1011-1344; 1873-2682
• DOI: 10.1016/1011-1344(95)07257-8

Several chlorophyll catabolites have been isolated and characterized from higher plants (angiosperms) and from a green algae (chlorophyte) during the last five years. A common feature of all chlorophyll catabolites isolated thus far is the unexpected regioselectivity of the oxidative cleavage of the macrocycle at the C(5)-methene bridge, yielding bile-pigment-like 19-formyl-1[21H, 23H]bilinones. Recent in vivo 18,18O 2-labelling experiments performed with the green algae Chlorella protothecoides showed unequivocally that a mono-oxygenase is involved in the primary oxidative cleavage step of the chlorophyll macrocycle. Moreover, the main red chlorophyll a catabolite from C. protothecoides has been chemically converted into the skeleton of the colourless catabolites isolated from angiosperms. On this basis, a likely catabolic pathway is outlined, which comprises all the products of chlorophyll breakdown isolated until now from both a chlorophyte and from higher plants.