Research Article J Mol Microbiol Biotechnol 2003 ; 6 : 41 -- 56 DOI : 10.1159 / 000073407 Dual Control by Regulators , GntH and GntR , of the GntII Genes for Gluconate Metabolism in Escherichia coli Ryouichi Tsunedomi Hanae Izu Takuya Kawai Mamoru Yamada Department of Biological Chemistry , Faculty of Agriculture , Yamaguchi University , Yamaguchi , Japan Key Words Gluconate metabolism W Gntll W gntR W gntH W Divergent promoter W Expressional regulation Abstract Escherichia coli possesses two systems , GntI and GntII , for gluconate uptake and catabolism , whose genes are regulated by GntR as a repressor and GntH as an activator , respectively .