Skip to main content
. 2008 Nov 24;284(5):3306–3313. doi: 10.1074/jbc.M803658200

FIGURE 3.

FIGURE 3.

The fluorescence spectra from the AK Mg2+ binding assay. The monotonic reduction of fluorescence intensity with increasing AK concentration is a clear indication of direct magnesium ion binding to AK. In the inset we have plotted the fluorescence intensity (at 520 nm) of the indicator versus AK concentration. We then fit the data to a curve by numerically solving the mass balance equations between the free Mg2+, Mg2+·indicator complex (known Kd = 4.7 mm), and Mg2+·enzyme complex (the unknown). The Kd value for E* was found to be 4.0 ± 1.5 mm.