Premium
THE CHROMOPHORES AS ENDOGENOUS SENSITIZERS INVOLVED IN THE PHOTOGENERATION OF SINGLET OXYGEN IN SPINACH THYLAKOIDS
Author(s) -
Jung Jin,
Kim HwanSu
Publication year - 1990
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.1751-1097.1990.tb01817.x
Subject(s) - singlet oxygen , chromophore , thylakoid , spinach , photochemistry , endogeny , chemistry , singlet state , oxygen , biophysics , biochemistry , chloroplast , biology , physics , excited state , organic chemistry , atomic physics , gene
— The photogeneration of singlet oxygen ( 1 O 2 ) from thylakoids and the chromophores involved as endogenous sensitizers were investigated using chloroplasts and thylakoids isolated from spinach. The blue light‐induced inhibition kinetics of photosynthetic electron transport and that of CTvCF, ATPase were also studied. The spectral dependence of the generation of 1 O 2 from thylakoid membranes, measured by the imidazole plus RNO method, clearly demonstrated that the Fe‐S centers play an important role in 1 O 2 generation, acting as sensitizers in thylakoids. The photoinhibition of the electron transport in isolated chloroplasts was strikingly depressed by a lipid‐soluble '0 2 quencher and enhanced by deuterium oxide substitution, indicating that the inhibition processes are mainly mediated by 1 O 2 which is produced via photodynamic activation. The involvement of chloroplast cytochromes in the production of 1 O 2 was deduced from the action spectrum for the photodynamic inhibition of the electron carrier chain. The results obtained from the kinetic studies appear consistent with the involvement of some components such as the Fe‐S centers and cytochrome chromophores of the carrier chain in the generation of 1 O 2 .