title: Blue light-induced Absorbance Changes in Membrane Fractions from Corn and Neurospora.
abstract: Blue light-induced absorbance changes were measured from differentially centrifuged membrane fractions from dark-grown coleoptiles of Zea mays L., and mycelia from an albino mutant of Neurospora crassa. Actinic irradiation caused changes in absorbance consistent with a flavinmediated reduction of a b-type cytochrome. Both corn and Neurospora showed similar light-minus-dark difference spectra, dose response curves, and kinetics of dark recovery after irradiation. The photoreducible cytochrome system from Neurospora showed the same distribution as the activity of a sodium-stimulated adenosine triphosphatase, thought to be a plasma membrane marker, in differential centrifugation experiments. The fraction showing the absorbance change did not co-sediment with the mitochondria, nor with the endoplasmic reticulum. Comparison of absorption spectra of fully oxidized, partially reduced, and fully reduced preparations showed that approximately a 30% reduction of the cytochromes involved with the process was needed to obtain the light-induced absorbance changes.
authors: Department of Plant Biology, Carnegie Institution of Washington, Stanford, California 94305.
authors: R D
authors: RD
authors: Brain
authors: J A
authors: JA
authors: Freeberg
authors: C V
authors: CV
authors: Weiss
authors: W R
authors: WR
authors: Briggs