FIG. 5.

NarX phosphorylation in the presence of various anions. Phosphorylation procedures were by the protocol described in the legend to Fig. 4. Where indicated, a 10× stock of KCl, NaCl, K₂SO4, Na₂SO₃, K₂HPO₄, NaClO₄, KHCO₃, or Na₂B₄O₇ was used in place of 10× KNO₂ or KNO₃. Final concentrations were 10 mM for each anion and 50 mM for HEPES buffer.