Inhibition of Dom5His and Dom5–9 binding to GAA by Man-6-P, Glc-6-P, and N-acetylglucosaminyl 6-phosphomethylmannoside diester. Aliquots of 500 nm Dom5His (A) and 50 nm Dom5–9 (B) were incubated with increasing concentrations of Glc-6-P (▿), Man-6-P (●), or N-acetylglucosaminyl 6-phosphomethylmannoside diester (○) and injected over a flow cell coupled with GAA diester. The Req from the resulting sensorgrams was plotted as a percent of the maximal response against the log of the inhibitor concentration. The Ki was determined using nonlinear regression (SigmaPlot, version 10.0).