in 3 mM NaAzide
The protein solution was in a buffer containing 25 mM NaCl, 100 mM NaMES/MES buffer, pH 7.5, 3 mM NaAzide
in 3 mM NaAzide. Buffer components were mixed to produce a pH of 4.7 according to a ratio calculated from the pKa. The actual pH of solution 2 was not measured.