Fig. 1.

Effect of sulfate on ADP and MgADP binding to the catalytic sites of βY331W-εdEcF₁. Fluorescence quenching induced by ADP (A) and MgADP (B) was measured in MTE buffer (A) and MTE buffer containing additional 3.2 mM MgAc₂ (B) as described under Experimental Procedures in the absence (circles) and presence of 2 mM (diamonds) and 20 mM (triangles) K₂SO₄. Solid and dashed lines in A and solid, dashed, and dotted lines in B represent the best fit of the data to Eq. 2, and dotted line in A represents the best fit of the data to Eq. 3, with the results of the fit shown in Table 1.