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LIGHT‐INDUCED ABSORBANCE CHANGES IN CELL‐FREE EXTRACTS OF NEUROSPORA CRASSA *
Author(s) -
Schmidt W.,
Butler W. L.
Publication year - 1976
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.1751-1097.1976.tb06800.x
Subject(s) - neurospora crassa , absorbance , sodium azide , chemistry , cytochrome , flavin group , flavin mononucleotide , cytochrome c , neurospora , cytochrome c oxidase , photochemistry , biochemistry , chromatography , enzyme , mitochondrion , mutant , gene
— The mycelium of Neurospora crassa was ground and extracted with buffer and separated into a soluble supernatant fraction and a particulate fraction by centrifugation. Both fractions were examined for light‐induced absorbance changes. Irradiation of the supernatant fraction caused a reversible photooxidation of cytochrome c which was inhibited by sodium azide or by dialysis. The action spectrum for the photooxidation showed that the response was mediated by an endogenous flavin. The photooxidation of cytochrome c , lost by dialysis, could be restored by adding flavin mononucleotide. Irradiation of the particulate fraction with blue light caused a reversible photoreduction of cytochrome c and cytochrome oxidase and, in some samples, of cytochrome b as well. The supernatant fraction showed photooxidation of cytochrome c rather than the more usual photoreductive changes because of the presence of super‐oxide dismutase activity.