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Action Spectra for Conversions of Phycochrome c from Nostoc muscorum
Author(s) -
BJÖRN G. S.,
BJÖRN L. O.
Publication year - 1978
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1978.tb02563.x
Subject(s) - absorbance , photostationary state , pigment , wavelength , darkness , spectral line , chemistry , action spectrum , visible spectrum , analytical chemistry (journal) , photochemistry , materials science , botany , chromatography , biology , physics , biochemistry , organic chemistry , optoelectronics , photoisomerization , isomerization , astronomy , catalysis
The reversibly photochromic pigment, phycochrome c, was extracted from the blue‐green alga Nostoc muscorum strain A. Action spectra were determined for in vitro conversions of the pigment from the short wavelength to the long wavelength form and vice versa. The action peak for the absorbance decrease at 650 nm is at 630 nm. During this decrease there is only a slight increase of the absorbance in the green region. Green and yellow light (maximum efficiency at 580 nm) completely restores absorbance at 650 nm. The observations are explained by the existence of three spectrally different forms of phycochrome c: P c 630 and P c 650 which equilibrate in darkness and P c 580 which is reversibly photoconvertible to P c 630 . We have also measured the absorbance changes brought about by saturating irradiations with light of various wavelengths (“photostationary state spectrum”). Extreme photostationary states were obtained with about 650 nm and 500 nm light.