3.5.99.10 down leucine antagonizes the activation by inducing transcriptional factor Lrp 757626 3.5.99.10 up the ridA gene of Escherichia coli is indirectly regulated by BglG through the transcriptional regulator Lrp in stationary phase. Gene ridA is positively regulated by leucine responsive regulatory protein (Lrp) and leucine antagonizes the activation by Lrp, putative Lrp binding site within the ridA promoter. Purified Lrp protein binds to ridA promoter in vitro 757626