title: Urea uptake and urease activity in Corynebacterium glutamicum.
abstract: When Corynebacterium glutamicum is grown with a sufficient nitrogen supply, urea crosses the cytoplasmic membrane by passive diffusion. A permeability coefficient for urea diffusion of 9 x 10(-7) cm s-1 was determined. Under conditions of nitrogen starvation, an energy-dependent urea uptake system was synthesized. Carrier-mediated urea transport was catalyzed by a secondary transport system linked with proton motive force. With a Km for urea of 9 microM, the affinity of this uptake system was much higher than the affinity of urease towards its substrate (Km approximately 55 mM urea). The maximum uptake velocity depended on the expression level and was relatively low [2-3.5 nmol min-1 (mg dry wt.)-1].
authors.affiliation: Institut für Biotechnologie 1, Forschungszentrum Jülich GmbH, Jülich, Germany.
authors.forename: R M
authors.initials: RM
authors.lastname: Siewe
authors.forename: B
authors.initials: B
authors.lastname: Weil
authors.forename: A
authors.initials: A
authors.lastname: Burkovski
authors.forename: L
authors.initials: L
authors.lastname: Eggeling
authors.forename: R
authors.initials: R
authors.lastname: Krämer
authors.forename: T
authors.initials: T
authors.lastname: Jahns
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis; D001692:Biological Transport; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002352:Carrier Proteins / Q000378:metabolism; D003352:Corynebacterium / Q000235:genetics / Q000378:metabolism*; D006918:Hydroxyurea / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D007700:Kinetics; D008564:Membrane Potentials; D009154:Mutation; D009584:Nitrogen / Q000502:physiology; D018892:Proton-Motive Force; D013890:Thiourea / Q000494:pharmacology; D014508:Urea / Q000378:metabolism*; D014510:Urease / Q000235:genetics / Q000378:metabolism*; D014634:Valinomycin / Q000494:pharmacology
chemical_list: D002352:Carrier Proteins; D007476:Ionophores; D014634:Valinomycin; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D000255:Adenosine Triphosphate; D014508:Urea; D014510:Urease; D013890:Thiourea; D009584:Nitrogen; D006918:Hydroxyurea