Oxidation versus Reductive Detoxification of SO(2) by Chloroplasts.
Intact chloroplasts isolated from spinach (Spinacia oleracea L. cv Yates) both oxidized and reduced added sulfite in the light. Oxidation was fast only when endogenous superoxide dismutase was inhibited by cyanide. It was largely suppressed by scavengers of oxygen radicals. After addition of O-acetylserine, chloroplasts reduced sulfite to cysteine and exhibited sulfite-dependent oxygen evolution. Cysteine synthesis from sulfite was faster than from sulfate. The results are discussed in relation to species-specific differences in the phytotoxicity of SO(2).
Ghisi
R
R
Institut für Botanik and Pharmazeutische Biologie der Universität Würzburg, Mittlerer Dallenbergweg 64, D-8700 Würzburg, Federal Republic of Germany.
Dittrich
A P
AP
Heber
U
U