TY - JOUR
T1 - Chlorophyll degradation in a Chlamydomonas reinhardtii mutant
T2 - An accumulation of pyropheophorbide a by anaerobiosis
AU - Doi, Michio
AU - Inage, Tetsuhiko
AU - Shioi, Yuzo
N1 - Funding Information:
This study was supported by grants from the Ministry of Education, Science, Sport and Culture of Japan (no. 12640631) and the Yamada Science Foundation.
PY - 2001
Y1 - 2001
N2 - Chlorophyll degradation was investigated in cells of a chlorophyll b-less mutant of Chlamydomonas reinhardtii under aerobic and anaerobic conditions. During degradation of chlorophyll under anaerobic conditions, chlorophyll catabolite P535, an open-tetrapyrrole, was not excreted, but pyropheophorbide a was accumulated as the end product with a transient accumulation of chlorophyllide a and pheophorbide a in cells, in contrast to the breakdown under aerobic conditions. It is likely that in the absence of oxygen, degradation of chlorophyll a proceeds to pyropheophorbide a by three consecutive reactions, dephytylation, metal-releasing and demethoxycarbonylation, and then stops due to a limitation of the oxygen that the monooxygenase reaction requires for bilin formation. A novel enzyme catalyzing demethoxycarbonylation of pheophorbide a was partially purified. The enzyme activity increased dependent on the age of cells, and its increase was completely suppressed by cycloheximide. Production of P535 was also dependent on cytoplasmic protein synthesis.
AB - Chlorophyll degradation was investigated in cells of a chlorophyll b-less mutant of Chlamydomonas reinhardtii under aerobic and anaerobic conditions. During degradation of chlorophyll under anaerobic conditions, chlorophyll catabolite P535, an open-tetrapyrrole, was not excreted, but pyropheophorbide a was accumulated as the end product with a transient accumulation of chlorophyllide a and pheophorbide a in cells, in contrast to the breakdown under aerobic conditions. It is likely that in the absence of oxygen, degradation of chlorophyll a proceeds to pyropheophorbide a by three consecutive reactions, dephytylation, metal-releasing and demethoxycarbonylation, and then stops due to a limitation of the oxygen that the monooxygenase reaction requires for bilin formation. A novel enzyme catalyzing demethoxycarbonylation of pheophorbide a was partially purified. The enzyme activity increased dependent on the age of cells, and its increase was completely suppressed by cycloheximide. Production of P535 was also dependent on cytoplasmic protein synthesis.
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U2 - 10.1093/pcp/pce057
DO - 10.1093/pcp/pce057
M3 - Article
C2 - 11382812
AN - SCOPUS:0034993573
VL - 42
SP - 469
EP - 474
JO - Plant and Cell Physiology
JF - Plant and Cell Physiology
SN - 0032-0781
IS - 5
ER -