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Further studies on the mechanism of stimulation of ATP formation by nigericin or ammonium chloride at low concentrations

Wei Jin, Li Youze

Shanghai Institute of Plant physiology,The Chinese Acakemy of Sciences. Shanghai 200032

Abstract

The results obtained were as follows:(1)The photophosphorylation activity and electron transport activity of PSⅠin both stacked and unstacked thylakoids of chloroplast were stimulated by low concentrations of nigericin in a low salt medium.(2)Only in the stacked thylakoids had low concentration of NH_4C1 a stimulative effect on the activity of cyclic or noncyclic PSP and that of electron transport through PS Ⅰor through both PS Ⅱ and PSⅠin low salt medium.(3)The stimulative effect of nigericin or NH_4C1 on PSP was not observed in high salt medium.(4)The inhibitory effect of nigericin or NH_4C1 on the formation of the high endergy state was greater in low salt medium than in high salt medium.(5)In low salt medium pyridine decreased the inhibitory effect of nigericin or NH_4C1 to stimmulate the formation of high energy state.These results show that localized protons exist in the stacked and unstacked thylakods,it may be transformed into the delocalized form.

Key words: Nigericin;NH_(4)Cl;Membrane-localized proton;Photophosphorylation

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Citing This Article：

Wei Jin, Li Youze. Further studies on the mechanism of stimulation of ATP formation by nigericin or ammonium chloride at low concentrations. Acta Physiol Sin 1996; 48 (2): (in Chinese with English abstract).