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. 1986 Apr;166(1):334–337. doi: 10.1128/jb.166.1.334-337.1986

Valinomycin-induced cation transport in vesicles does not reflect the activity of K+ transport systems in Escherichia coli.

K Altendorf, W Epstein, A Löhmann
PMCID: PMC214598  PMID: 3514580

Abstract

Transport systems for K+ in Escherichia coli are not detectable in membrane vesicles, but vesicles will take up K+ (and Rb+) in the presence of valinomycin. It is generally believed that valinomycin acts as a lipid-soluble cation carrier and that it does not interact with or activate cation transport systems. This view is challenged by Bhattacharyya et al. (Proc. Natl. Acad. Sci. USA 68:1448-1492, 1971), who reported reduced uptake in vesicles from E. coli mutants with K+ transport defects. We reexamined this question with some of the same mutants and were unable to confirm a correlation of valinomycin-induced vesicle transport with transport properties in intact cells. We found great variability in transport activity of vesicles from these E. coli K-12 strains and believe such variability as well as possible contamination with intact cells accounts for the earlier report. Our data do not support the idea that valinomycin-mediated transport in vesicles is related to physiological K+ transport systems.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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