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NITRATE REDUCTASE—A KEY ENZYME IN BLUE LIGHT‐PROMOTED CONIDIATION AND ABSORBANCE CHANGE OF NEUROSPORA
Author(s) -
Klemm Eva,
Ninnemann Helga
Publication year - 1979
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.1751-1097.1979.tb07102.x
Subject(s) - nitrate reductase , chemistry , flavin group , conidiation , absorbance , nitrate , neurospora , photochemistry , biochemistry , reductase , enzyme , neurospora crassa , chromatography , organic chemistry , mutant , gene
— Neurospora , when starved for several hours, can be stimulated by blue light to conidiate and also shows a blue light‐inducible, flavin‐mediated absorbance change near 425 nm due to photoreduc‐tion of a h‐type cytochrome. Under the same physiological conditions, nitrate reductase activity (NADPH‐dependent nitrate reduction) decreases and the activity of its small subunit (methylviologen‐to‐nitrate reductase activity) increases. The increased activity is membrane associated (plasma membrane and mitochondria). The methylviologen‐to‐nitrate activity increase can also be brought about by treating mycelium briefly with diluted acetone. It is, therefore, interpreted as change within the nitrate reductase molecule (configuration change or separation of subunits with changed exposure of active sites). After acetone treatment the blue light‐induced absorbance change can be observed immediately in the mycelium. Nitrate reductase with its flavin and protoheme prosthetic groups seems to be involved in both events, the induction of conidiation and in the described absorbance change.