Evidence that the low-affinity K super(+) transport system of Rhodobacter capsulatus is a uniporter. The effects of ammonium on the transporter

Comparison of the rate of accumulation of super(86)Rb super(+) by intact cells of Rhodobacter capsulatus during short periods of illumination with the RB super(+)-dependent membrane ionic current measured by electrochromism supports the view that both activities reflect the operation of a low-affini...

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Bibliographic Details
Published in:Archives of microbiology 1992-01, Vol.157 (2), p.125-130
Main Authors: Golby, P, Cotton, NPJ, Carver, M, Jackson, J B
Format: Article
Language:English
Subjects:
Rhodobacter capsulatus
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Summary:Comparison of the rate of accumulation of super(86)Rb super(+) by intact cells of Rhodobacter capsulatus during short periods of illumination with the RB super(+)-dependent membrane ionic current measured by electrochromism supports the view that both activities reflect the operation of a low-affinity K super(+) transport system. The addition of NH super(+) sub(4) to a cell suspension led to an increase in membrane ionic current but failed to inhibit the accumulation of super(86)Rb super(+) during illumination. The presence of K super(+) and NH super(+) sub(4) inhibited the increase in cellular ATP levels at the onset of illumination. This effect was prevented by Cs super(+).
ISSN:0302-8933