Characterization of a secondary uptake system for L-glutamate in Corynebacterium glutamicum

A new transport system for the uptake of L-glutamate was characterized in Corynebacterium glutamicum strain Delta glu, in which the previously described binding protein-dependent glutamate uptake system is not present. Kinetic characterization revealed a highly specific secondary transport system, dependent on sodium ions, Glutamate uptake showed Michaelis-Menten kinetics, with a K-m of 0.6 mM and a V-max of 15 nmol min(-1) (mg dw)(-1). For the co-transported sodium ions, a relatively low K-m of 3.3 mM was determined.