TABLE 2.

Abilities of various compounds to inhibit the uptake of choline by BetT expressed in E. coli MKH13(pMEbetT)a

ChemicalConcn (mM)% Inhibition of [14C]choline uptake
Choline1095
Choline175
Acetylcholine1084
Acetylcholine140
Phosphorylcholine110
Glycine betaine100
Proline100
  • a Cells were grown in M63 medium amended with 0.5 M NaCl, and uptake was realized with 100 μM [14C]choline. The results are expressed as percent inhibition of uptake and are means of three independent experiments with variations of less than 10%. The uptake rate in the absence of competitors was 8.0 nmol/min/mg of protein.