This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Kang, S Y Search for Related Content PubMed PubMed Citation Articles by Kang, S Y

 Previous Article  |  Next Article 

J Bacteriol. 1978 December; 136(3): 867-873

Mechanism of autoenergized transport and nature of energy coupling for D-lactate in Escherichia coli.

ABSTRACT

To fully energize the active transport systems of Escherichia coli, it is common practice to preincubate the cells for 10 min with 10 or 20 mM concentration of a compound that can serve as an energy source. This paper shows that the active accumulation of D-lactate can be achieved within 1 min with only 50 micron D-lactate serving as an energy source for its own uptake in starved cells (autoenergization). The cells were strain DL54 which had been induced by growth in the presence of D-lactate. Uninduced cells were not able to show autoenergized D-lactate uptake under these conditions. The induced cells were also able to transport proline in the presence of 100 micron D-lactate as sole energy source. The D-lactate-dependent dehydrogenase activity in inverted French press vesicles was comparable for the induced and uninduced cells. The same was true for respiration of whole cells in the presence of 20 mM D-lactate. However, the Vmax for D-lactate transport of induced cells was six times higher than that of uninduced cells. It appears that a sufficient number of high-affinity carrier molecules in the cytoplasmic membrane are necessary for the autoenergized transport of D-lactate. A similar conclusion was reached for the autoenergized uptake of glycerol-3-phosphate by Escherichia coli strain 7. The active transport of D-lactate is driven by the protonmotive force.

This article has been cited by other articles:

• Rodriguez, C., Kwon, O., Georgellis, D. (2004). Effect of D-Lactate on the Physiological Activity of the ArcB Sensor Kinase in Escherichia coli. J. Bacteriol. 186: 2085-2090 [Abstract] [Full Text]