Effects of divalent cations on NADH-linked electron transfer in corn root plasma membrane
1995
Tu, S.I. | Patterson, D. | Braver, D. | Hsu, A.F.
The effects of calcium (Ca2+), cadmium (Cd2+), and copper (Cu2+) cations on NADH-linked electron transfer in corn root plasma membrane vesicles were investigated. The reduction of both cytochrome c and ferricyanide were slightly stimulated by Ca2+ but not significantly affected by Cd2+. However, Cd2+ induced a redox-linked increase in light scattering suggesting an increase in the size/volume of the vesicles. The presence of micromolar levels of Cu2+ decreased the reduction rates of both cytochrome c and ferricyanide. However, in contrast to ferricyanide reduction, Cu inhibition to the cytochrome d reduction was more effective and was less sensitive to ionic strength. Copper inhibition changed the Michaelis-Menten dependence of the ferricyanide reduction but not that of cytochrome c. These results suggest that the reduction of cytochrome c and ferricyanide must occur at different membrane sites.
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