Format

Send to

Choose Destination
Biochim Biophys Acta. 1987 Dec 11;905(2):231-9.

Properties of a Na+-coupled serine-threonine transport system in Escherichia coli.

Author information

1
Department of Microbiology, Faculty of Pharmaceutical Sciences, Okayama University, Japan.

Abstract

Based on the following experimental results we conclude that the serine-threonine transport system in Escherichia coli is a Na+-coupled cotransport system. (1) Addition of serine to cell suspensions induced H+ efflux in the presence of Na+. (2) Addition of serine to cell suspensions induced Na+ uptake by cells. (3) Imposition of an artificial electrochemical potential of Na+ in starved cells induced serine uptake. Some of these phenomena were observed when threonine was added instead of serine or inhibited when cells were preincubated with threonine. The Na+/serine (threonine) cotransport system was considerably repressed when cells were grown on a mixture of amino acids. Serine transport in cells grown in the absence of amino acids mixture was stimulated by Na+. The half maximum concentration of Na+ was 21 microM. Sodium ion increased the Vmax of serine transport without affecting the Km.

PMID:
2825778
DOI:
10.1016/0005-2736(87)90451-2
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center