The molecular mechanism of dicarboxylic acid transport in escherichia coli K 12

1977 ◽  
Vol 7 (3-4) ◽  
pp. 463-480 ◽  
Author(s):  
Theodore C. Y. Lo
Keyword(s):  
Escherichia Coli ◽  
Dicarboxylic Acid ◽  
Molecular Mechanism ◽  
Acid Transport ◽  
K 12

scholarly journals Succinate uptake and related proton movements in Escherichia coli K12

1975 ◽  
Vol 152 (3) ◽  
pp. 647-654 ◽  
Author(s):  
S J Gutowski ◽  
H Rosenberg
Keyword(s):  
Escherichia Coli ◽  
Dicarboxylic Acid ◽  
Transport System ◽  
Dicarboxylic Acids ◽  
Acid Transport ◽  
Cationic Form ◽  
Whole Cells ◽  
Escherichia Coli K12 ◽  
Proton Uptake

1. The apparent Km values for succinate uptake by whole cells of Escherichia coli K12 depend on pH in the range 6.5-7.4.2. Uptake of succinate in lightly buffered medium is accompanied by proton uptake. 3. The apparent Km values for succinate uptake and for succinate-induced proton uptake are similar. 4. Approximately two protons enter the cell with each succinate molecule. 5. The pattern of inhibition of succinate uptake is similar to that of succinate-induced proton uptake. 6. Uptake of fumarate and malate, which share the succinate-transport system, is also accompanied by the uptake of approximately two protons per molecule of fumarate or malate. 7. Uptake of aspartate by the dicarboxylic acid-transport system is accompanied by the uptake of approximatley two protons per molecule of asparatate. 8. It is concluded that uptake of dicarboxylic acids by the dicarboxylic acid-transport system is obligatorily coupled to proton uptake such that succinate, malate and fumarate are taken up in electroneutral form and asparate is taken up in cationic form. 9. These results are consistent with, though they do not definitely prove, the energization of succinate uptake of the deltapH.

Sign in / Sign up

Export Citation Format

Share Document