FIGURE 4.

A, MIF catalyzes the tautomerization of the chromogenic substrate dopachrome methyl ester to a colorless indole derivative. B, the time course of the inhibition of rhMIF tautomerase activity by 10 μm (●), 20 μm (○), and 30 μm (▴) PEITC is shown. Results are representative of three experiments. C, time course of the inhibition of cellular MIF tautomerase activity by 1 μm (●), 2 μm (○), and 4 μm (▴) PEITC is shown. Values are the mean ± S.E. of three experiments. D, concentration dependence of the inhibition of cellular MIF tautomerase activity after a 30-min exposure to PEITC (○), sulforaphane (▾), or benzyl isothiocyanate (▿) is shown. Values are the mean ± S.E. of at least three experiments. E, Jurkat cells were treated with increasing concentrations of PEITC for 30 min. Cell lysates were prepared, and the ability of MIF to bind Affi-PEITC was measured. A representative gel is shown.