Glutamine uptake by a sodium-dependent secondary transport system inCorynebacterium glutamicum |
| |
Authors: | Ruth M Siewe Brita Weil Reinhard Krämer |
| |
Institution: | (1) Institut für Biotechnologie 1, Forschungszentrum Jülich, D-52425 Jülich, Germany |
| |
Abstract: | Corynebacterium glutamicum took up glutamine by a sodium-dependent secondary transport system. Both the membrane potential and the sodium gradient were
driving forces. Glutamine uptake showed Michaelis-Menten kinetics, with aK
m of 36 μM and aV
max of 12.5 nmol min−1 (mg dry weight)−1 at pH 7. Despite a pH optimum in the alkaline range around pH 9, it was shown that uncharged glutamine is the transported
species. The affinity for the cotransported sodium was relatively low; an apparentK
m of 1.4 mM was determined. Among various substrates tested, only asparagine, when added in 50-fold excess, led to an inhibition
of glutamine transport. It was concluded that glutamine uptake occurs via a specific transport system in symport with at least
one sodium ion. |
| |
Keywords: | Glutamine Amino acid transport Solute uptake Corynebacterium glutamicum |
本文献已被 SpringerLink 等数据库收录! |