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PHOTOINACTIVATION OF A Chlamydomonas MUTANT(NL–11) IN THE PRESENCE OF METHIONINE: ROLES OF H 2 O 2 and O ‐ 2
Author(s) -
Takahama Umeo,
Egashira Takeshi,
Nakamura Kazuo
Publication year - 1985
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1985.tb03463.x
Subject(s) - chlamydomonas reinhardtii , methionine , mutant , catalase , superoxide dismutase , wild type , chlamydomonas , chemistry , biochemistry , microbiology and biotechnology , biology , enzyme , amino acid , gene
— A mutant of Chlamydomonas reinhardtii (NL–11) isolated from a wild type (137c+) was inactivated in the light in the presence of methionine at concentrations where the wild type was not inactivated. The inactivation was suppressed by either catalase or superoxide dismutase (SOD). Light‐induced H 2 O 2 formation and nitroblue tetrazolium (NBT) reduction inNL–11 were greater than those in the wild type. Methionine stimulated both the H 2 O 2 formation and the NBT reduction inNL–11 as well as the wild type. The light‐induced NBT reduction inNL–11 in the presence of methionine was partially suppressed by externally added SOD suggesting the participation of O ‐ 2 . These results suggest that the hypersensitivity ofNL–11 to methionine in the light is due to stimulated formation of H 2 O 2 and O ‐ 2 .