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. Author manuscript; available in PMC: 2012 Apr 17.
Published in final edited form as: Sci Signal. 2011 Dec 13;4(203):ra86. doi: 10.1126/scisignal.2002329

Figure 1. Redox-dependent inactivation and reactivation of PTP1B.

Figure 1

A. Time dependent inactivation of PTP1B by H2S. The phosphatase activity of PTP1B was monitored in the presence of the following concentrations of H2S, 10 μM (●), 20 μM (■), 50 μM (▲), 100 μM (▼), 200 μM (◆). Inset, the concentration dependence of the rate of inactivation was used to derive the second order rate constant, 22.4 ± 1.8 M−1s−1.

B. Time dependent reactivation of PTP1B by DTT. The following concentrations of DTT were used 5 mM (●), 10 mM (■), 15 mM (▲), 20 mM (▼). Inset, the concentration dependence of the rate of reactivation was used to derive the second order rate constant, 0.24 ± 0.1 M−1s−1. Data are representative of three independent determinations.

C and D. Binding of fluorescently-labeled phosphopeptide substrate (5′-FAM-ENDpYINASL) to WT (●), C215S (■), or D181A (▲) mutant forms of PTP1B. The change in fluorescence polarization is plotted as a function of time. The assays were performed in the absence of H2S (C) or following incubation with 100 μM H2S for 10 min (D).