title: Inhibition of photosynthetic oxygen evolution in non-vesicular preparations releases Mn2+ into a restricted aqueous compartment.
abstract: Release of Mn2+ following inhibition of the water-splitting enzyme by treatment with Zn2+ was studied in two preparations derived from chloroplasts: oxygen-evolving Photosystem II membrane fragments and Tween-20 treated thylakoid membranes. In both cases the released Mn2+ was retained in the membrane fraction on centrifugation in spite of the fact that the two preparations are known to be non-vesicular. This suggests that upon inhibition Mn2+ is released into an aqueous compartment more restricted than the thylakoid lumen. We propose that this compartment is formed from the various proteins of the Photosystem II complex.
mesh_terms: D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism*; D007425:Intracellular Membranes / Q000378:metabolism; D007700:Kinetics; D008345:Manganese / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D010788:Photosynthesis; D010944:Plants / Q000378:metabolism; D013431:Sulfates / Q000494:pharmacology*; D015032:Zinc / Q000494:pharmacology*; D019287:Zinc Sulfate
chemical_list: D013431:Sulfates; D008345:Manganese; D019287:Zinc Sulfate; D015032:Zinc; D010100:Oxygen