FIGURE 2.

Kinetics of GSTP1-1 nitrosation monitored by intrinsic fluorescence. A, representative transients showing the decrease in fluorescence when 1 μm of different cysteine mutants of GSTP1-1 was mixed with 500 μm nitrosating agent (GSNO or CysNO) at 37 °C. Curves were normalized to have the same starting fluorescence. B, S-nitrosation of 1 μm wild-type GSTP1-1 with 500 μm GSNO. The data were fit to a triple-exponential function. The residuals show an excellent fit to the data when the three exponential terms are fixed to the observed rate constants for nitrosation at Cys⁴⁷, Cys¹⁰¹, and the alternate site, respectively, determined from fitting the data in B.