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Ammonium (methylammonium) is the co‐repressor of nitrate reductase in Chlamydomonas reinhardii
Author(s) -
Franco Antonio R.,
Cárdenas Jacobo,
Fernández Emilio
Publication year - 1984
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(84)81217-x
Subject(s) - derepression , nitrate reductase , ammonium , glutamine synthetase , chemistry , chlamydomonas , nitrate , biochemistry , reductase , ammonia , glutamine , enzyme , psychological repression , amino acid , organic chemistry , mutant , gene expression , gene
Methylammonium cannot be used as a nitrogen source by the green alga Chlamydomonas reinhardii and, like ammonia, caused the repression of nitrate reductase without affecting the photosynthetic activity. Glutamine synthetase catalyzed the conversion ofmethylammonium to a single product, identified as γ‐ N ‐methylglutamine, which accumulated in the cells. Derepression of nitrate reductase was accompanied by a decrease in the intracellular concentration of methylammonium and a concomitant accumulation of γ‐ N ‐methylglutamine inside the cells. These facts strongly suggest that ammonium (methylammonium) per se, and not a product of its metabolism, is the co‐repressor of nitrate reductase in C. reinhardii