title: L-carnitine uptake by Escherichia coli.
abstract: The uptake of L-carnitine by Escherichia coli 044 K74 which is able to metabolize L-carnitine to gamma-butyrobetaine under anaerobic conditions was studied. The uptake system of E. coli was induced in the presence of L-carnitine or crotonobetaine. The optimum influx of L-carnitine was found to take place at 37 degrees C in phosphate buffer, pH 7.5. On the basis of the temperature dependence of the uptake rate an activation energy of 53.5 kJ/mol was estimated. The transport of L-carnitine was energy dependent. The kinetics of L-carnitine entry followed the Michaelis-Menten relationship yielding a Km value of 5.3 x 10(-4) M and a Vmax of 154 nmol/min.mg protein. The transport system showed considerable structural specificity for trimethylamine carboxylic molecules. The results suggest that E. coli possesses an inducible, active and carrier-mediated uptake system for L-carnitine.
authors: Sektion Biowissenschaften, Karl-Marx-Universität Leipzig, DDR.
authors: H
authors: H
authors: Jung
authors: K
authors: K
authors: Jung
authors: H P
authors: HP
authors: Kleber
mesh_terms: D019297:2,4-Dinitrophenol; D000693:Anaerobiosis; D001622:Betaine / Q000031:analogs & derivatives / Q000378:metabolism; D001667:Binding, Competitive; D001693:Biological Transport, Active; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002331:Carnitine / Q000378:metabolism*; D004140:Dinitrophenols / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D013696:Temperature; D014475:Uncoupling Agents / Q000494:pharmacology
chemical_list: D004140:Dinitrophenols; D014475:Uncoupling Agents; D001622:Betaine; C002889:gamma-butyrobetaine; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; C025237:crotonic acid betaine; D019297:2,4-Dinitrophenol; D002331:Carnitine