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Experiments were performed to investigate the physiological dynamics of metabolic pathways in the GntII system genes of Escherichia coli through a biochemical analysis of the pathway enzyme gluconate and its accompanying intermediates and growth experiments involving mutants with lesions in particular sites in the pathway. DNA sequence analysis and nuclear magnetic resonance studies were performed on the mutants. Findings suggested that the GntII system genes encoded a pathway for catabolism of L-idonate in which D-gluconate was an intermediate.

Gluconate metabolism in Escherichia coli is under the control of a group of genes under two main systems. The transporter genes which belong to the GntI system are negatively regulated by the gene GntR. The product of this regulatory gene contains a helix turn helix motif which is similar to that of the lac operon. GntR negatively regulates the gluconate regulon gene by binding to the operator sequence.

Single-copy gnt::lacZ fusion and Northern hybridization analysis were utilized to characterize the expression of the Escherichia coli gntT gene and determine the biochemical function of its protein product. Northern hybridization analysis of the Escherichia coli gntT gene indicated the presence of properties that were characteristic of integral membrane transport proteins. Furthermore, gntT gene expression was enhanced during the logarithmic phase indicating the role of GntT in promoting microbial growth.

A transcriptional factor called glutamate uptake regulatory protein (Grp) has been identified in Zymomonas mobilis. The protein increased glutamate uptake in E. coli but inhibited the secondary H+

Structural and functional analysis of the gluABCD DNA fragment of gram-positive Corynebacterium glutamicum reveals that the glutamate uptake system of the bacterium depends on binding proteins and that the system contains all the structures for control and transport on the DNA fragment analyzed. The gluA, gluB, gluC and gluD gene form an operon, as indicated by the terminator structure present downstream of gluD. Kinetic analysis with globomycin-grown cells indicates that the tethering of C-glutamicin binding protein is essential for proper functioning.